Control of Post-Meiotic Gene Expression by H2A.L.2

H2A.L.2 is a specific variant of the H2A histone that accumulates late in the post-meiotic stages of mouse spermatogenesis, coinciding with the appearance of transition proteins (TPs). Since TP accumulation occurs during a period of general transcriptional shutdown, we hypothesized that the accumulation of TP and H2A.L.2 would not influence the transcriptome of condensing spermatids. To test this hypothesis, we isolated total RNA from fractionated mouse spermatogenic cells, including spermatocytes, round spermatids, and condensing spermatids. We then generated transcriptomes from both wild-type cells and cells deficient in H2A.L.2. Analysis of these transcriptomes confirmed our hypothesis, showing no significant differences in gene expression between cells with or without H2A.L.2. These findings suggest that H2A.L.2 plays a structural role in the nucleosome-to-protamine transition rather than a regulatory role in transcription.