Mettl3-/Mettl14-mediated mRNA N6-methyladenosine modulates murine spermatogenesis

Abstract

Spermatogenesis is a differentiation process during which diploid spermatogonial stem cells (SSCs) produce haploid spermatozoa. This highly specialized process is precisely controlled at the transcriptional, posttranscriptional, and translational levels. Here we report that N-methyladenosine (mA), an epitranscriptomic mark regulating gene expression, plays essential roles during spermatogenesis. We present comprehensive mA mRNA methylomes of mouse spermatogenic cells from five developmental stages: undifferentiated spermatogonia, type A spermatogonia, preleptotene spermatocytes, pachytene/diplotene spermatocytes, and round spermatids. Germ cell-specific inactivation of the mA RNA methyltransferase Mettl3 or Mettl14 with Vasa-Cre causes loss of mA and depletion of SSCs. mA depletion dysregulates translation of transcripts that are required for SSC proliferation/differentiation. Combined deletion of Mettl3 and Mettl14 in advanced germ cells with Stra8-GFPCre disrupts spermiogenesis, whereas mice with single deletion of either Mettl3 or Mettl14 in advanced germ cells show normal spermatogenesis. The spermatids from double-mutant mice exhibit impaired translation of haploid-specific genes that are essential for spermiogenesis. This study highlights crucial roles of mRNA mA modification in germline development, potentially ensuring coordinated translation at different stages of spermatogenesis.

A dynamic reversible RNA N6‐methyladenosine modification: current status and perspectives

“…In the zebrafish embryos with METTL3 deficiency, hematopoietic stem cells cannot be produced as usual (Ear & Lin, ). METTL3‐/METTL14‐mediated mRNA N 6 ‐methyladenosine modulates murine spermatogenesis (Lin et al, ).…”

Integrative analyses of the RNA modification machinery reveal tissue- and cancer-specific signatures

“…RNA modifications can influence pre-mRNA splicing, mRNA export, turnover, and translation, which are controlled in the male germline to ensure coordinated gene expression [35]. Recent works have shown that m6A depletion in mice dysregulates translation of transcripts that are required for spermatogonial proliferation and differentiation [34]. Moreover, m 5 C modifications have been shown to be essential for transmission of diet-induced epigenetic information across generations in the epididymis [53].…”

“…It is well established that mRNA levels do not always correlate well with protein levels [59]. Thus, to assess whether our findings would hold at the protein level, we performed immunohistochemistry in both testis and epididymis to characterize the expression patterns of 4 RMPs at the protein level: (i) NSUN7, a putative m 5 C methyltransferase that has been shown to affect sperm motility [56,60]; (ii) NSUN2, an m 5 C tRNA methyltransferase involved in sperm differentiation [61]; (iii) METTL14, a component of the m 6 A methyltransferase complex, which has been shown to be dynamically regulated during spermatogenesis [34], and (iv) HENMT1, a piRNA 2'-O-methyltransferase responsible for transposon silencing during spermatogenesis [5] (Figure 3D, see also Figure S3E).…”

Functional role of GKAP1 in the regulation of male germ cell spontaneous apoptosis and sperm number

“…Spermatogenesis is a complex and orderly biological process that depends on a precisely controlled cascade of diverse genes regulating germ cell proliferation (Lin et al, ; Wang et al, ). To produce mature male gametes, chromosomal reduction during division produces a haploid genome in each daughter cell and this is followed by morphological differentiation of these cells, which leads to the formation of mature sperm (Loveland et al, ).…”