| SOHLH1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Identifiers | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Aliases | SOHLH1, C9orf157, NOHLH, SPATA27, TEB2, bA100C15.3, bHLHe80, spermatogenesis and oogenesis specific basic helix-loop-helix 1, ODG5, SPGF32 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 610224; MGI: 2684956; GeneCards: SOHLH1 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Wikidata | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Spermatogenesis- and oogenesis-specific basic helix-loop-helix-containing protein 1 is a protein which in humans is encoded by the gene SOHLH1. It functions as a transcription factor, which means it binds with DNA and helps regulate which genes get translated into RNA and eventually encoded into proteins. SOHLH1, in particular, is involved in the differentiation and production of both sperm cells (spermatogenesis) and egg cells (oogenesis). Beyond these two kinds of germ cells, it is also expressed in ovarian follicles, which help support and mature oocytes (immature egg cells). Mutations which interfere with the functioning of the SOHLH1 gene in humans are associated with infertility and other reproductive system conditions.
As its name suggests, SOHLH1 is a transcription factor of the basic helix–loop–helix family. It is involved in the development of both ovaries and testes. In the reproductive system, SOHLH1 (together with its homolog SOHLH2) are predominantly expressed in germ cells and early ovarian follicles (primordial and primary). Follicles fail to develop properly in the ovaries of knock-out mice, and are completely missing by 3 weeks after birth. These defects are thought to be related to SOHLH1’s regulation of genes specific to germ cells, notably including the transcription factor LHX8 which it directly regulates. Other directly regulated genes include ZP1 and ZP3.
Pathogenic variants in human are associated with both male and female reproductive system dysfunction. In the female reproductive system, homozygous variants have been associated with a failure of the ovaries to develop normally. Instead, the gonads develop into non-functional fibrous tissue (a condition called gonadal dysgenesis). The specific subtype associated with SOHLH1 is called Ovarian Dysgenesis 5. In the male reproductive system, heterozygous variants are associated with infertility due to a failure in sperm production, which is called nonobstructive azoospermia. This SOHLH1-associated subtype is called Spermatogenic Failure 32.