Positioning of sperm tail longitudinal columns depend on Nsun7, an RNA binding protein destabilizing elongated spermatid transcripts.

Spermatozoid's flagella assemble in transcriptionally silent spermatids and thus depends on post-transcriptional regulation of gene expression. Mutations in Nsun7 gene are known to cause male infertility in human and mice. We identified m5C-specific Nsun7 RNA methyltransferase as a protein present in elongated spermatids and interacting with RNAs specific for this type of spermatozoid's precursor cells.