Phosphoribosyl Pyrophosphate Synthetase 1 Like 1 (PRPS1L1)

PRPS1L1 is specifically expressed in the testis, and encodes a protein that is highly homologous to the two subunits of phosphoribosylpyrophosphate synthetase encoded by human X-linked genes, PRPS1 and PRPS2. Peptide sequencing and mutagenesis experiments showed that translation of PRPS3 initiates at an ACG codon that specifies methioninerather than threonine, and that this methionine is subsequently removed, resulting in a mature protein with an N-terminal proline. In vitro transcription and cell-free translation resulted in a protein with an apparent molecular mass of 38 kD. Northern blot analysis detected a 1.4-kb transcript in human testis. Prps3 expression was not detected in testis of 3-week-old rats, but its expression increased after 4 weeks, roughly correlating with the appearance of primary spermatocytes.