Heterologous expression of bovine histone H1foo into porcine fibroblasts alters the transcriptome profile but not embryo development following nuclear transfer.

Abstract

Purpose: Somatic cell nuclear transfer (SCNT) is a valuable tool for investigating reprogramming mechanisms and creating animal clones for applications in production, conservation, companionship, and biomedical research. However, SCNT efficiency remains low. Expression of nuclear proteins associated with an undifferentiated chromatin state, such as the oocyte-specific variant of the linker histone H1 (H1foo), represents a strategy for improving reprogramming outcomes, but this approach has not been tested in the context of SCNT.

Methods: Bovine H1foo (bH1foo) was transfected into porcine fibroblasts via electroporation for expression until SCNT. The transcriptomic profile of these cells was analyzed, and their potential as donor cells for SCNT was evaluated 48 h post-electroporation.

Results: Strong nuclear localization of bH1foo persisted for 48 h post-electroporation. A total of 447 genes were differentially expressed, and lower levels of H3K4me3 and H3K27me3 were detected in bH1foo-expressing cells, indicating changes in chromatin remodeling and function. Embryo development and total cell number per blastocyst were similar between SCNT embryos produced with control and bH1foo-expressing cells. mRNA levels of genes involved in embryonic genome activation were comparable between embryos derived from control and bH1foo-expressing cells on days 3 and 4 of development, suggesting that bH1foo did not disrupt this critical process.

Conclusions: The heterologous expression of bovine H1foo altered the chromatin function of porcine fibroblasts without impairing development to the blastocyst stage following SCNT. These results highlight the potential of expressing nuclear proteins as a strategy to enhance cell reprogramming and cloning efficiency, including interspecies cloning applications.