Among the about 20,000 genes in the human proteome there are still many rather unknown but potentially interesting proteins that deserve some extra attention. Here we will focus on C10orf53, a gene specifically expressed in the testis.

The testis is the male genital gland and has three main functions, to produce spermatozoa, the male germ cell, to secret sex hormones, primarily testosterone, and to regulate the reproductive function together with the hypothalamus-pituitary unit.

Transcriptome analysis shows that 77% of all human proteins are expressed in this important organ, which also has the highest number of enriched genes so far found in any tissue. More than 1200 genes show enriched expression in the testis compared to other tissues.

Many of these are well-known but among them we also find C10orf53, a rather unknown gene with neither known function nor protein evidence in the UniProt database. That this "Gene Doe" has a function related to the testis is however strongly suggested by the expression profile in both bulk and single cell RNA seq, which show enrichment in testis and more specifically in early and late spermatids. Expression clustering and correlation of tissue and single cell RNA seq data further show C10orf53 to cluster together with other genes known to be related to spermatid development and spermatogenesis. Immunohistochemical staining of the protein confirms these findings by showing specific expression in early and late spermatids in testis.