Single-cell transcriptome reveals a testis-specific expression profile of TCEA in human spermatogenesis

Transcription elongation factor A (TCEA) is a eukaryotic transcriptional molecule, required for a formation of initiation and elongation of gene transcription-mediated RNA polymerase II (RNAPII) complex, to promote transcription-coupled nucleotide excision repair (TC-NER) after RNAPII backtracking recovery. TCEA shares three isoforms in which TCEA1 is ubiquitously expressed among all eukaryotic cells. We found a spermatogenesis TCEA1 and TCEA2 expression profile has a unique transcriptional programme, compared with embryogenesis. Moreover, the testis-specific TCEA2 profile correlates with gene transcription, whereas TCEA1 specifically correlates with genes transcribed for Nuclear excision repair (NER) during human spermatogenesis. We also found that the expression activation of RNF20, a TCEA1 inhibitor, leads to expressional TCEA1 reduction, but having no direct impact on TCEA2 expression, implying the potential RNF20-dependent transcriptional switching of TCEA2 in transcriptional regulation during spermatogenesis. Our analysis defined a transcriptional bursting event where transcription-coupled repair (both Base excision repair and Nuclear excision repair) is a major pathway highly expressed in early spermatogenesis, supporting the transcriptional scanning hypothesis of which mutation of transcribed genes is effectively repaired as proposed by Xia B., et al. (2020).