In the cell nucleus, the chromatin is formed by the building block, nucleosome which is comprised of a 146 bp of DNA fragment wrapping around a histone core protein formed by two of each histone H2A, H2B, H3, and H4 protein. During spermatogenesis, the dramatic changes observed in the nucleus are the reprogramming of the whole genome and histone – protamine exchange via the involvement of histone variants, which leads to tight compaction of the genome in the sperm nuclei. The disruption of genes encoding for testis-specific histone variants, in general, leading a serious impact on sperm production, for example, H3T. Being a histone H2B variant, H2BFM is thought to be a testis-specific histone variant, however, the function of the protein in the spermatogenesis is remains largely unknow...[ Read more ]

In the cell nucleus, the chromatin is formed by the building block, nucleosome which is comprised of a 146 bp of DNA fragment wrapping around a histone core protein formed by two of each histone H2A, H2B, H3, and H4 protein. During spermatogenesis, the dramatic changes observed in the nucleus are the reprogramming of the whole genome and histone – protamine exchange via the involvement of histone variants, which leads to tight compaction of the genome in the sperm nuclei. The disruption of genes encoding for testis-specific histone variants, in general, leading a serious impact on sperm production, for example, H3T. Being a histone H2B variant, H2BFM is thought to be a testis-specific histone variant, however, the function of the protein in the spermatogenesis is remains largely unknown until now. In this study, we reported that H2BFM is specifically expressed in early stages of spermatogenesis. The nucleosome containing H2BFM is an unstable nucleosome, about 40% more unstable than the canonical nucleosome, similar to other testis-specific histone H2B variant, H2BFWT. Furthermore, H2BFM in overexpressed cultured cell interacts with RNA processing factors, suggest that H2BFM may be related in the transcription activation. These results suggest that H2BFM may function in remain active transcription in human spermatogenesis.

Keywords: Histone Variants, H2BFW, H2BFM, Optical tweezers, Spermatogenesis