V. Sannino, A. M. Kolinjivadi, G. Baldi, V. Costanzo
The correct duplication of genetic information is essential to maintain genome stability, which is lost in cancer cells. Replication fork integrity is ensured by a number of DNA metabolism proteins that assist replication of chromatin regions difficult to replicate due to their intrinsic DNA sequence composition, coordinate repair of DNA molecules resulting from aberrant replication events or protect replication forks in the presence of lesions impairing their progression. Some DNA metabolism genes involved in DNA repair are essential in higher eukaryotes even in unchallenged conditions, suggesting the existence of biological processes requiring these specialized functions in organisms with complex genomes. The impact on cell survival of null mutants of many DNA metabolism genes has precluded complete in depth analysis of their function. Cell free extracts represent a fundamental tool to overcome survival issues. The Xenopus laevis egg cell free extract is an ideal system to study replication-associated functions of essential genes. We are taking advantage of this system together with innovative imaging and proteomic based experimental approaches to characterize the molecular function of essential DNA metabolism proteins. Using this approach we have uncovered the role of some essential homologous recombination and fork protection proteins in chromosomal DNA replication and we have characterized some of the factors required for faithful replication of specific vertebrate genomic regions. This approach will be instrumental to study the molecular mechanisms underlying the function of a number of essential DNA metabolism proteins involved in the maintenance of genome stability in complex genomes.
{"title":"Studying essential DNA metabolism proteins in Xenopus egg extract.","authors":"V. Sannino, A. M. Kolinjivadi, G. Baldi, V. Costanzo","doi":"10.1387/IJDB.160103VC","DOIUrl":"https://doi.org/10.1387/IJDB.160103VC","url":null,"abstract":"The correct duplication of genetic information is essential to maintain genome stability, which is lost in cancer cells. Replication fork integrity is ensured by a number of DNA metabolism proteins that assist replication of chromatin regions difficult to replicate due to their intrinsic DNA sequence composition, coordinate repair of DNA molecules resulting from aberrant replication events or protect replication forks in the presence of lesions impairing their progression. Some DNA metabolism genes involved in DNA repair are essential in higher eukaryotes even in unchallenged conditions, suggesting the existence of biological processes requiring these specialized functions in organisms with complex genomes. The impact on cell survival of null mutants of many DNA metabolism genes has precluded complete in depth analysis of their function. Cell free extracts represent a fundamental tool to overcome survival issues. The Xenopus laevis egg cell free extract is an ideal system to study replication-associated functions of essential genes. We are taking advantage of this system together with innovative imaging and proteomic based experimental approaches to characterize the molecular function of essential DNA metabolism proteins. Using this approach we have uncovered the role of some essential homologous recombination and fork protection proteins in chromosomal DNA replication and we have characterized some of the factors required for faithful replication of specific vertebrate genomic regions. This approach will be instrumental to study the molecular mechanisms underlying the function of a number of essential DNA metabolism proteins involved in the maintenance of genome stability in complex genomes.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"13 1","pages":"221-227"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82285023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this short review is to describe the contribution of Xenopus laevis egg extracts to the discovery and understanding of the regulation and function of the serine/threonine kinase Aurora-A. The power of these extracts to recapitulate cell cycle events makes them a precious tool to decipher complex biological processes at the molecular level, including the mechanisms that affect Aurora-A (post-translational modifications) and mechanisms in which Aurora-A plays a crucial role (bipolar spindle assembly). We focus on the results obtained in cell-free extracts, but we also give an updated overview of Aurora A functions found in other systems.
{"title":"Aurora-A: an expedition to the pole of the spindle in Xenopus egg extracts.","authors":"J. Kubiak, C. Prigent","doi":"10.1387/IJDB.160189JK","DOIUrl":"https://doi.org/10.1387/IJDB.160189JK","url":null,"abstract":"The aim of this short review is to describe the contribution of Xenopus laevis egg extracts to the discovery and understanding of the regulation and function of the serine/threonine kinase Aurora-A. The power of these extracts to recapitulate cell cycle events makes them a precious tool to decipher complex biological processes at the molecular level, including the mechanisms that affect Aurora-A (post-translational modifications) and mechanisms in which Aurora-A plays a crucial role (bipolar spindle assembly). We focus on the results obtained in cell-free extracts, but we also give an updated overview of Aurora A functions found in other systems.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"38 1","pages":"255-261"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74498907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Dȩbowski, Mohammed El Dika, J. Malejczyk, R. Zdanowski, C. Prigent, J. Tassan, M. Kloc, M. Lachowicz, J. Kubiak
During the cell cycle, cyclin dependent kinase 1 (CDK1) and protein phosphatase 2A (PP2A) play major roles in the regulation of mitosis. CDK1 phosphorylates a series of substrates triggering M-phase entry. Most of these substrates are dephosphorylated by PP2A. To allow phosphorylation of CDK1 substrates, PP2A is progressively inactivated upon M-phase entry. We have shown previously that the interplay between these two activities determines the timing of M-phase entry. Slight diminution of CDK1 activity by the RO3306 inhibitor delays M-phase entry in a dose-dependent manner in Xenopus embryo cell-free extract, while reduction of PP2A activity by OA inhibitor accelerates this process also in a dose-dependent manner. However, when a mixture of RO3306 and OA is added to the extract, an intermediate timing of M-phase entry is observed. Here we use a mathematical model to describe and understand this interplay. Simulations showing acceleration and delay in M-phase entry match previously described experimental data. CDC25 phosphatase is a major activator of CDK1 and acts through CDK1 Tyr15 and Thr14 dephosphorylation. Addition of CDC25 activity to our mathematical model was also consistent with our experimental results. To verify whether our assumption that the dynamics of CDC25 activation used in this model are the same in all experimental variants, we analyzed the dynamics of CDC25 phosphorylation, which reflect its activation. We confirm that these dynamics are indeed very similar in control extracts and when RO3306 and OA are present separately. However, when RO3306 and OA are added simultaneously to the extract, activation of CDC25 is slightly delayed. Integration of this parameter allowed us to improve our model. Furthermore, the pattern of CDK1 dephosphorylation on Tyr15 showed that the real dynamics of CDK1 activation are very similar in all experimental variants. The model presented here accurately describes, in mathematical terms, how the interplay between CDK1, PP2A and CDC25 controls the flexible timing of M-phase entry.
{"title":"Flexibility vs. robustness in cell cycle regulation of timing of M-phase entry in Xenopus laevis embryo cell-free extract.","authors":"M. Dȩbowski, Mohammed El Dika, J. Malejczyk, R. Zdanowski, C. Prigent, J. Tassan, M. Kloc, M. Lachowicz, J. Kubiak","doi":"10.1387/IJDB.160134JK","DOIUrl":"https://doi.org/10.1387/IJDB.160134JK","url":null,"abstract":"During the cell cycle, cyclin dependent kinase 1 (CDK1) and protein phosphatase 2A (PP2A) play major roles in the regulation of mitosis. CDK1 phosphorylates a series of substrates triggering M-phase entry. Most of these substrates are dephosphorylated by PP2A. To allow phosphorylation of CDK1 substrates, PP2A is progressively inactivated upon M-phase entry. We have shown previously that the interplay between these two activities determines the timing of M-phase entry. Slight diminution of CDK1 activity by the RO3306 inhibitor delays M-phase entry in a dose-dependent manner in Xenopus embryo cell-free extract, while reduction of PP2A activity by OA inhibitor accelerates this process also in a dose-dependent manner. However, when a mixture of RO3306 and OA is added to the extract, an intermediate timing of M-phase entry is observed. Here we use a mathematical model to describe and understand this interplay. Simulations showing acceleration and delay in M-phase entry match previously described experimental data. CDC25 phosphatase is a major activator of CDK1 and acts through CDK1 Tyr15 and Thr14 dephosphorylation. Addition of CDC25 activity to our mathematical model was also consistent with our experimental results. To verify whether our assumption that the dynamics of CDC25 activation used in this model are the same in all experimental variants, we analyzed the dynamics of CDC25 phosphorylation, which reflect its activation. We confirm that these dynamics are indeed very similar in control extracts and when RO3306 and OA are present separately. However, when RO3306 and OA are added simultaneously to the extract, activation of CDC25 is slightly delayed. Integration of this parameter allowed us to improve our model. Furthermore, the pattern of CDK1 dephosphorylation on Tyr15 showed that the real dynamics of CDK1 activation are very similar in all experimental variants. The model presented here accurately describes, in mathematical terms, how the interplay between CDK1, PP2A and CDC25 controls the flexible timing of M-phase entry.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"54 2 1","pages":"305-314"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74317937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Professor Takeo Kishimoto's research has an enormous impact on the cell cycle field. Although his favorite model has always been a starfish oocyte, he has used many other model organisms in his research. Cell-free extracts have been wildly used in his laboratory as a very useful tool to answer cell cycle research questions. Recently, professor Kishimoto discovered the identity of the M-phase promoting factor (MPF) that was thought for years to be cyclin-dependent kinase 1 (CDK1). However, Takeo Kishimoto found that MPF consists in fact of two kinases: CDK1 and Greatwall kinase. While CDK1 phosphorylates mitotic substrates, Greatwall kinase allows these substrates to persist in their phosphorylated state because it regulates phosphatase PP2A, which dephosphorylates the majority of CDK1 substrates. When I started to interview Prof. Kishimoto, I was mostly interested in his experiences with cell-free extracts. However, as you will see below we almost immediately turned to the problem of the identity of MPF. This is fully understandable because the identity of MPF seems to be a major interest in Takeo's scientific career. I hope readers will enjoy this interview and will be able to learn about many aspects of scientific research, which do not usually appear in regular research papers.
{"title":"MPF, starfish oocyte and cell-free extract in the background - an interview with Takeo Kishimoto.","authors":"J. Kubiak, T. Kishimoto","doi":"10.1387/IJDB.160348JK","DOIUrl":"https://doi.org/10.1387/IJDB.160348JK","url":null,"abstract":"Professor Takeo Kishimoto's research has an enormous impact on the cell cycle field. Although his favorite model has always been a starfish oocyte, he has used many other model organisms in his research. Cell-free extracts have been wildly used in his laboratory as a very useful tool to answer cell cycle research questions. Recently, professor Kishimoto discovered the identity of the M-phase promoting factor (MPF) that was thought for years to be cyclin-dependent kinase 1 (CDK1). However, Takeo Kishimoto found that MPF consists in fact of two kinases: CDK1 and Greatwall kinase. While CDK1 phosphorylates mitotic substrates, Greatwall kinase allows these substrates to persist in their phosphorylated state because it regulates phosphatase PP2A, which dephosphorylates the majority of CDK1 substrates. When I started to interview Prof. Kishimoto, I was mostly interested in his experiences with cell-free extracts. However, as you will see below we almost immediately turned to the problem of the identity of MPF. This is fully understandable because the identity of MPF seems to be a major interest in Takeo's scientific career. I hope readers will enjoy this interview and will be able to learn about many aspects of scientific research, which do not usually appear in regular research papers.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"49 1","pages":"193-200"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88717138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Analysis of cell-free extracts has allowed us to understand many of the fundamental processes of cell physiology and pathology, including those involved in embryo development and cancer. This methodology is being continuously modified and improved. Papers selected for this Special Issue will show readers the plethora of systems and applications of this methodology.
{"title":"Cell-free extracts in Development and Cancer Research for over 40 years.","authors":"J. Kubiak","doi":"10.1387/IJDB.160222JK","DOIUrl":"https://doi.org/10.1387/IJDB.160222JK","url":null,"abstract":"Analysis of cell-free extracts has allowed us to understand many of the fundamental processes of cell physiology and pathology, including those involved in embryo development and cancer. This methodology is being continuously modified and improved. Papers selected for this Special Issue will show readers the plethora of systems and applications of this methodology.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"15 1","pages":"189-191"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74460218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chromatin, primarily a complex of DNA and histone proteins, is the physiological form of the genome. Chromatin is generally repressive for transcription and other information transactions that occur on DNA. A wealth of post-translational modifications on canonical histones and histone variants encode regulatory information to recruit or repel effector proteins on chromatin, promoting and further repressing transcription and thereby form the basis of epigenetic information. During metazoan oogenesis, large quantities of histone proteins are synthesized and stored in preparation for the rapid early cell cycles of development and to elicit maternal control of chromatin assembly pathways. Oocyte and egg cell-free extracts of the frog Xenopus laevis are a compelling model system for the study of chromatin assembly and transcription, precisely because they exist in an extreme state primed for rapid chromatin assembly or for transcriptional activity. We show that chromatin assembly rates are slower in the X. laevis oocyte than in egg extracts, while conversely, only oocyte extracts transcribe template plasmids. We demonstrate that rapid chromatin assembly in egg extracts represses RNA Polymerase II dependent transcription, while pre-binding of TATA-Binding Protein (TBP) to a template plasmid promotes transcription. Our experimental evidence presented here supports a model in which chromatin assembly and transcription are in competition and that the onset of zygotic genomic activation may be in part due to stable transcriptional complex assembly.
{"title":"Chromatin assembly and transcriptional cross-talk in Xenopus laevis oocyte and egg extracts.","authors":"Wei-lin Wang, D. Shechter","doi":"10.1387/IJDB.160161DS","DOIUrl":"https://doi.org/10.1387/IJDB.160161DS","url":null,"abstract":"Chromatin, primarily a complex of DNA and histone proteins, is the physiological form of the genome. Chromatin is generally repressive for transcription and other information transactions that occur on DNA. A wealth of post-translational modifications on canonical histones and histone variants encode regulatory information to recruit or repel effector proteins on chromatin, promoting and further repressing transcription and thereby form the basis of epigenetic information. During metazoan oogenesis, large quantities of histone proteins are synthesized and stored in preparation for the rapid early cell cycles of development and to elicit maternal control of chromatin assembly pathways. Oocyte and egg cell-free extracts of the frog Xenopus laevis are a compelling model system for the study of chromatin assembly and transcription, precisely because they exist in an extreme state primed for rapid chromatin assembly or for transcriptional activity. We show that chromatin assembly rates are slower in the X. laevis oocyte than in egg extracts, while conversely, only oocyte extracts transcribe template plasmids. We demonstrate that rapid chromatin assembly in egg extracts represses RNA Polymerase II dependent transcription, while pre-binding of TATA-Binding Protein (TBP) to a template plasmid promotes transcription. Our experimental evidence presented here supports a model in which chromatin assembly and transcription are in competition and that the onset of zygotic genomic activation may be in part due to stable transcriptional complex assembly.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"37 1","pages":"315-320"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81202144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chromatin is the complex of DNA and histone proteins that is the physiological form of the eukaryotic genome. Chromatin is generally repressive for transcription, especially so during early metazoan development when maternal factors are explicitly in control of new zygotic gene expression. In the important model organism Xenopus laevis, maturing oocytes are transcriptionally active with reduced rates of chromatin assembly, while laid eggs and fertilized embryos have robust rates of chromatin assembly and are transcriptionally repressed. As the DNA-to-cytoplasmic ratio decreases approaching the mid-blastula transition (MBT) and the onset of zygotic genome activation (ZGA), the chromatin assembly process changes with the concomitant reduction in maternal chromatin components. Chromatin assembly is mediated in part by histone chaperones that store maternal histones and release them into new zygotic chromatin. Here, we review literature on chromatin and transcription in frog embryos and cell-free extracts and highlight key insights demonstrating the roles of maternal and zygotic histone deposition and their relationship with transcriptional regulation. We explore the central historical and recent literature on the use of Xenopus embryos and the key contributions provided by experiments in cell-free oocyte and egg extracts for the interplay between histone chaperones, chromatin assembly, and transcriptional regulation. Ongoing and future studies in Xenopus cell free extracts will likely contribute essential new insights into the interplay between chromatin assembly and transcriptional regulation.
{"title":"Chaperone-mediated chromatin assembly and transcriptional regulation in Xenopus laevis.","authors":"Takashi Onikubo, D. Shechter","doi":"10.1387/IJDB.130188DS","DOIUrl":"https://doi.org/10.1387/IJDB.130188DS","url":null,"abstract":"Chromatin is the complex of DNA and histone proteins that is the physiological form of the eukaryotic genome. Chromatin is generally repressive for transcription, especially so during early metazoan development when maternal factors are explicitly in control of new zygotic gene expression. In the important model organism Xenopus laevis, maturing oocytes are transcriptionally active with reduced rates of chromatin assembly, while laid eggs and fertilized embryos have robust rates of chromatin assembly and are transcriptionally repressed. As the DNA-to-cytoplasmic ratio decreases approaching the mid-blastula transition (MBT) and the onset of zygotic genome activation (ZGA), the chromatin assembly process changes with the concomitant reduction in maternal chromatin components. Chromatin assembly is mediated in part by histone chaperones that store maternal histones and release them into new zygotic chromatin. Here, we review literature on chromatin and transcription in frog embryos and cell-free extracts and highlight key insights demonstrating the roles of maternal and zygotic histone deposition and their relationship with transcriptional regulation. We explore the central historical and recent literature on the use of Xenopus embryos and the key contributions provided by experiments in cell-free oocyte and egg extracts for the interplay between histone chaperones, chromatin assembly, and transcriptional regulation. Ongoing and future studies in Xenopus cell free extracts will likely contribute essential new insights into the interplay between chromatin assembly and transcriptional regulation.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"1 1","pages":"271-276"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74945922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Vigneron, Perle Robert, Khaled Hached, Lena Sundermann, S. Charrasse, J. Labbé, A. Castro, T. Lorca
Entry into mitosis requires the coordinated activation of various protein kinases and phosphatases that together activate sequential signaling pathways allowing entry, progression and exit of mitosis. The limiting step is thought to be the activation of the mitotic Cdk1-cyclin B kinase. However, this model has recently evolved with new data showing that in addition to the Cdk1-cyclin B complex, Greatwall (Gwl) kinase is also required to enter into and maintain mitosis. This new concept proposes that entry into mitosis is now based on the combined activation of both kinases Cdk1-cyclin B and Gwl, the former promoting massive phosphorylation of mitotic substrates and the latter inhibiting PP2A-B55 phosphatase responsible for dephosphorylation of these substrates. Activated Gwl phosphorylates both Arpp19 and ENSA, which associate and inhibit PP2A-B55. This pathway seems relatively well conserved from yeast to humans, although some differences appear based on models or techniques used. While Gwl is activated by phosphorylation, its inactivation requires dephosphorylation of critical residues. Several phosphatases such as PP1, PP2A-B55 and FCP1 are required to control the dephosphorylation and inactivation of Gwl and a properly regulated mitotic exit. Gwl has also been reported to be involved in cancer processes and DNA damage recovery. These new findings support the idea that the Gwl-Arpp19/ENSA-PP2A-B55 pathway is essential to achieve an efficient division of cells and to maintain genomic stability.
{"title":"The master Greatwall kinase, a critical regulator of mitosis and meiosis.","authors":"S. Vigneron, Perle Robert, Khaled Hached, Lena Sundermann, S. Charrasse, J. Labbé, A. Castro, T. Lorca","doi":"10.1387/IJDB.160155TL","DOIUrl":"https://doi.org/10.1387/IJDB.160155TL","url":null,"abstract":"Entry into mitosis requires the coordinated activation of various protein kinases and phosphatases that together activate sequential signaling pathways allowing entry, progression and exit of mitosis. The limiting step is thought to be the activation of the mitotic Cdk1-cyclin B kinase. However, this model has recently evolved with new data showing that in addition to the Cdk1-cyclin B complex, Greatwall (Gwl) kinase is also required to enter into and maintain mitosis. This new concept proposes that entry into mitosis is now based on the combined activation of both kinases Cdk1-cyclin B and Gwl, the former promoting massive phosphorylation of mitotic substrates and the latter inhibiting PP2A-B55 phosphatase responsible for dephosphorylation of these substrates. Activated Gwl phosphorylates both Arpp19 and ENSA, which associate and inhibit PP2A-B55. This pathway seems relatively well conserved from yeast to humans, although some differences appear based on models or techniques used. While Gwl is activated by phosphorylation, its inactivation requires dephosphorylation of critical residues. Several phosphatases such as PP1, PP2A-B55 and FCP1 are required to control the dephosphorylation and inactivation of Gwl and a properly regulated mitotic exit. Gwl has also been reported to be involved in cancer processes and DNA damage recovery. These new findings support the idea that the Gwl-Arpp19/ENSA-PP2A-B55 pathway is essential to achieve an efficient division of cells and to maintain genomic stability.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"49 1","pages":"245-254"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79092079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Methylation of the guanosine cap structure at the 5' end of mRNA is essential for efficient translation of all eukaryotic cellular mRNAs, gene expression and cell viability and promotes transcription, splicing, polyadenylation and nuclear export of mRNA. In the current study, we present the spatial expression pattern of the Xenopus laevis rnmt homologue. A high percentage of protein sequence similarity, especially within the methyltransferase domain, as well as an increased expression in the cells of the transcriptionally active stages, suggests a conserved RNA cap methylation function. Spatial expression analysis identified expression domains in the brain, the retina, the lens, the otic vesicles and the branchial arches.
{"title":"Expressional characterization of mRNA (guanine-7) methyltransferase (rnmt) during early development of Xenopus laevis.","authors":"Ashwin Lokapally, Sanjeeva Metikala, T. Hollemann","doi":"10.1387/ijdb.150409th","DOIUrl":"https://doi.org/10.1387/ijdb.150409th","url":null,"abstract":"Methylation of the guanosine cap structure at the 5' end of mRNA is essential for efficient translation of all eukaryotic cellular mRNAs, gene expression and cell viability and promotes transcription, splicing, polyadenylation and nuclear export of mRNA. In the current study, we present the spatial expression pattern of the Xenopus laevis rnmt homologue. A high percentage of protein sequence similarity, especially within the methyltransferase domain, as well as an increased expression in the cells of the transcriptionally active stages, suggests a conserved RNA cap methylation function. Spatial expression analysis identified expression domains in the brain, the retina, the lens, the otic vesicles and the branchial arches.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"21 1","pages":"65-9"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79259730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gordon Barry Pierce, my great mentor and long-time friend died in November 2015 at the age of 90 years. We will all miss him. What we are left with, however, are reminiscences of moments we spent with him, his jokes and stories to be retold and passed along, titbits of advice, and pearls of his common-sense Canadian wisdom. A vision of a better world to which he contributed so much. Scientific contributions too numerous to list, many of which had major impact on us who were interested in the same problems as he was. Seminal discoveries that impacted the progress in several fields of scientific endeavor. Major new concepts of oncology and developmental biology that opened new vistas and revolutionized our thinking about the crucial problems of biology and medicine. Unforgettable seminars and lectures. Unquenchable love for science. And much more that, nevertheless, can be summarized in two wondrous exclamations: What a man! What a life!
{"title":"In Memoriam - Prof. G. Barry Pierce (1925-2015).","authors":"I. Damjanov","doi":"10.1387/ijdb.160014id","DOIUrl":"https://doi.org/10.1387/ijdb.160014id","url":null,"abstract":"Gordon Barry Pierce, my great mentor and long-time friend died in November 2015 at the age of 90 years. We will all miss him. What we are left with, however, are reminiscences of moments we spent with him, his jokes and stories to be retold and passed along, titbits of advice, and pearls of his common-sense Canadian wisdom. A vision of a better world to which he contributed so much. Scientific contributions too numerous to list, many of which had major impact on us who were interested in the same problems as he was. Seminal discoveries that impacted the progress in several fields of scientific endeavor. Major new concepts of oncology and developmental biology that opened new vistas and revolutionized our thinking about the crucial problems of biology and medicine. Unforgettable seminars and lectures. Unquenchable love for science. And much more that, nevertheless, can be summarized in two wondrous exclamations: What a man! What a life!","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"1 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73131362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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