Cold Spring Harbor perspectives in biology最新文献

The neuromuscular junction (NMJ) is a highly reliable synapse to carry the control of the motor commands of the nervous system over the muscles. Its development, organization, and synaptic properties are highly structured and regulated to support such reliability and efficacy. Yet, the NMJ is also highly plastic, able to react to injury, and able to adapt to changes. This balance between structural stability and synaptic efficacy on one hand and structural plasticity and repair on another hand is made possible by perisynaptic Schwann cells (PSCs), glial cells at this synapse. They regulate synaptic efficacy and structural plasticity of the NMJ in a dynamic, bidirectional manner owing to their ability to decode synaptic transmission and by their interactions with trophic-related factors. Alteration of these fundamental roles of PSCs is also important in the maladapted response of NMJs in various diseases and in aging.

Fish telomere lengths vary significantly across the numerous species, implicating diverse life strategies and environmental adaptations. Zebrafish have telomere dynamics that are comparable to humans and are emerging as a key model in which to unravel the systemic effects of telomere shortening on aging and interorgan communication. Here, we discuss zebrafish telomere biology, focusing on the organismal impact of telomere attrition beyond cellular senescence, with particular emphasis on how telomeric shortening in specific tissues can unleash widespread organ dysfunction and disease. This highlights a novel aspect of tissue communication, whereby telomere shortening in one organ can propagate through biological networks, influencing the aging process systemically. These discoveries position zebrafish as a valuable model for studying the complex interactions between telomeres, aging, and tissue cross talk, providing important insights with direct relevance to human health and longevity.

The natural ends of chromosomes resemble double-strand breaks (DSBs), which would activate the DNA damage response (DDR) pathway without the protection provided by a specialized protein complex called shelterin. Over the past decades, extensive research has uncovered the mechanism of action and the high degree of specialization provided by the shelterin complex to prevent aberrant activation of DNA repair machinery at chromosome ends in somatic cells. However, recent findings have revealed striking differences in the mechanisms of end protection in stem cells compared to somatic cells. In this review, we discuss what is known about the differences between stem cells and somatic cells regarding chromosome end protection.

Saccharomyces cerevisiae, a model organism in telomere biology, has been instrumental in pioneering a comprehensive understanding of the molecular processes that occur in the absence of telomerase across eukaryotes. This exploration spans investigations into telomere dynamics, intracellular signaling cascades, and organelle-mediated responses, elucidating their impact on proliferative capacity, genome stability, and cellular variability. Through the lens of budding yeast, numerous sources of cellular heterogeneity have been identified, dissected, and modeled, shedding light on the risks associated with telomeric state transitions, including the evasion of senescence. Moreover, the unraveling of the intricate interplay between the nucleus and other organelles upon telomerase inactivation has provided insights into eukaryotic evolution and cellular communication networks. These contributions, akin to milestones achieved using budding yeast, such as the discovery of the cell cycle, DNA damage checkpoint mechanisms, and DNA replication and repair processes, have been of paramount significance for the telomere field. Particularly, these insights extend to understanding replicative senescence as an anticancer mechanism in humans and enhancing our understanding of eukaryotes' evolution.

Hybridization, or interbreeding between different taxa, was traditionally considered to be rare and to have a largely detrimental impact on biodiversity, sometimes leading to the breakdown of reproductive isolation and even to the reversal of speciation. However, modern genomic and analytical methods have shown that hybridization is common in some of the most diverse clades across the tree of life, sometimes leading to rapid increase of phenotypic variability, to introgression of adaptive alleles, to the formation of hybrid species, and even to entire species radiations. In this review, we identify consensus among diverse research programs to show how the field has progressed. Hybridization is a multifaceted evolutionary process that can strongly influence species formation and facilitate adaptation and persistence of species in a rapidly changing world. Progress on testing this hypothesis will require cooperation among different subdisciplines.

Gregor Mendel's seminal publication, "Versuche über Pflanzen-Hybriden" ("Experiments on Plant Hybrids"), which appeared in 1866, is regarded as one of the founding documents of genetics and has therefore been translated several times. In 2016, with the support of the British Society for the History of Science (BSHS), we produced a new online translation of Mendel's paper, alongside a facsimile and transcription of the original German text and an extensive commentary that offered historical and linguistic insights into nearly every sentence. The translation and commentary were made available on the BSHS website and 4 years later were published as a book by Masaryk University Press. In this paper, we build on the introduction to our translation to reflect and include some important developments in the scholarship around Mendel that have taken place since the translation was first published.

While silent in normal differentiated human tissues, telomerase is reactivated in most human cancers. Thus, telomerase is an almost universal oncology target. This update describes preclinical and clinical advancements using a variety of approaches to target telomerase. These include direct telomerase inhibitors, G-quadruplex DNA-interacting ligands, telomerase-based vaccine platforms, telomerase promoter-driven attenuated viruses, and telomerase-mediated telomere targeting approaches. While imetelstat has been recently approved by the Food and Drug Administration (FDA), several other approaches are in late-stage clinical development. The pros and cons of the major approaches will be reviewed.

Telomere function is critical for genomic stability; in the context of a functional TP53 response, telomere erosion leads to a G₁/S cell-cycle arrest and the induction of replicative senescence, a process that is considered to underpin the ageing process in long-lived species. Abrogation of the TP53 pathway allows for continued cell division, telomere erosion, and the complete loss of telomere function; the ensuing genomic instability facilitates clonal evolution and malignant progression. Telomeres display extensive length heterogeneity in the population that is established at birth, and this affects the individual risk of a broad range of diseases, including cardiovascular disease and cancer. In this perspective, I discuss telomere length heterogeneity at the levels of the population, individual, and cell, and consider how the dynamics of these essential chromosomal structures contribute to human disease.

Three-dimensional (3D) printing can be beneficial to tissue engineers and the regenerative medicine community because of its potential to rapidly build elaborate 3D structures from cellular and material inks. However, predicting changes to the structure and pattern of printed tissues arising from the mechanical activity of constituent cells is technically and conceptually challenging. This perspective is targeted to scientists and engineers interested in 3D bioprinting, but from the point of view of cells and tissues as mechanically active living materials. The dynamic forces generated by cells present unique challenges compared to conventional manufacturing modalities but also offer profound opportunities through their capacity to self-organize. Consideration of self-organization following 3D printing takes the design and execution of bioprinting into the fourth dimension of cellular activity. We therefore propose a framework for dynamic bioprinting that spatiotemporally guides the underlying biology through reconfigurable material interfaces controlled by 3D printers.

It is well-known that the rediscovery of Mendelian genetics at the turn of twentieth century offered Darwin's theory a much-needed lifeline, by showing how Fleeming Jenkins' famous "blending" objection could be rebutted. However, Mendelism has another fortuitous consequence for evolutionary biology that is less widely appreciated. By bequeathing the notion of allelism to biology, Mendelism shows how two difficult conceptual issues for evolutionary theory can be resolved. The first issue concerns the notion of population. By definition, evolutionary change is change in the composition of a population, but what is the relevant definition of "population"? The second issue concerns Darwin's notion of "struggle for existence." Is this struggle an essential part of evolution by natural selection or not? In a Mendelian population, these issues can be simply resolved, since the selective competition is at root between alleles at a locus, who are necessarily playing a zero-sum game, rather than between organisms, who may or may not be doing so.