Expression pattern of RNA demethylase ALKBH5 in fetal and adult human testis

N⁶-methyladenosine (m⁶A) is a common post-transcriptional modification of RNAs in eukaryotic cells, which is involved in various biological processes. ALKBH5 is one of the m⁶A demethylases and has been reported to play important roles in mouse testis. But the function of ALKBH5 in human testis remained undiscovered. Here we aimed to analyze the expression and location of ALKBH5 in fetal and adult human testis. We found that fetal human testis is characterized by the formation of testis cords filled with pre-spermatogonia and pre-Sertoli cells, which is significantly distinct from the convoluted seminiferous epithelium in adult testis. ALKBH5 is not only widely expressed in adult human testis, but also expressed in VASA positive pre-spermatogonia, SOX9 positive pre-Sertoli cells, and CYP11A positive pre-Leydig cells in fetal human testis. Moreover, bioinformatics analysis of published RNA-sequencing data (GSE63392) revealed the expression of ALKBH5 in human fetal germ cells is upregulated with the increase of gestational weeks. Thus, our results indicate the potential role of ALKBH5 in fetal human testis development and function.