HGNC Approved Gene Symbol: PRPS2
Cytogenetic location: Xp22.2 Genomic coordinates (GRCh38): X:12,791,412-12,824,222 (from NCBI)
Five-phosphoribosyl 1-pyrophosphate (PPRibP), an essential substrate and a critical regulator in the purine, pyrimidine, and pyridine nucleotide production pathways, is synthesized from MgATP and ribose 5-phosphate by the enzyme PPRibP synthetase (EC 2.7.6.1). By cDNA cloning, Taira et al. (1987) found 2 distinct PPRibP synthetase subunits, PRS I (PRPS1; 311850) and PRS II. By screening a testis library with a rat PRS II cDNA, Iizasa et al. (1989) isolated cDNAs encoding human PRS II. The predicted 318-amino acid protein shares 99% identity with rat PRS II. Northern blot analysis revealed that PRS II is expressed as a 2.7-kb mRNA in testis.
By Northern blot analysis using rat Prps2 as probe, Taira et al. (1989) detected a 2.7-kb transcript in human testis and in 2 human cell lines.
Wang et al. (1992) demonstrated that the PRPS2 gene is inactivated with lyonization but that it lies between 2 genes that escape inactivation, STS (300747) distally and ZFX (314980) proximally. The PRPS1 gene also undergoes X inactivation. Wang et al. (1992) commented that it was not known which of the 2 PRPS loci is altered in patients with inherited PRPS superactivity. The ZFX gene, which escapes X-inactivation, is bracketed proximally by the POLA gene (312040) which, like PRPS2, undergoes inactivation. The A1S9T (314370) locus in the proximal short arm and the RPS4X gene (312760) in the proximal long arm are other loci that escape inactivation and are interspersed among genes that do undergo X-inactivation. Furthermore, the XIST gene (314670), located at Xq13, is transcribed only from the inactive X chromosome.
By using a rat cDNA probe for PRPS1 and a human cDNA probe for PRPS2, Taira et al. (1989) showed in DNA from somatic cell hybrids and in spot-blot hybridization of flow-sorted chromosomes that whereas PRPS1 is on Xq21-qter, PRPS2 is on Xpter-q21. Furthermore, 2 PRPS1-related genes were identified on chromosomes 7 and 9. By a combination of in situ hybridization and study of human/rodent somatic cell hybrids, Becker et al. (1990) assigned the PRPS2 locus to Xp22.3-p22.2. Despite the striking homology in the cDNA sequence and deduced amino acid sequence, PRPS1 and PRPS2 are encoded by genes on opposite arms of the X chromosome.
Becker, M. A., Heidler, S. A., Bell, G. I., Seino, S., Le Beau, M. M., Westbrook, C. A., Neuman, W., Shapiro, L. J., Mohandas, T. K., Roessler, B. J., Palella, T. D. Cloning of cDNAs for human phosphoribosylpyrophosphate synthetases 1 and 2 and X chromosome localization of PRPS1 and PRPS2 genes. Genomics 8: 555-561, 1990. [PubMed: 1962753] [Full Text: https://doi.org/10.1016/0888-7543(90)90043-t]
Iizasa, T., Taira, M., Shimada, H., Ishijima, S., Tatibana, M. Molecular cloning and sequencing of human cDNA for phosphoribosyl pyrophosphate synthetase subunit II. FEBS Lett. 244: 47-50, 1989. [PubMed: 2538352] [Full Text: https://doi.org/10.1016/0014-5793(89)81159-7]
Taira, M., Iizasa, T., Yamada, K., Shimada, H., Tatibana, M. Tissue-differential expression of two distinct genes for phosphoribosyl pyrophosphate synthetase and existence of the testis-specific transcript. Biochim. Biophys. Acta 1007: 203-208, 1989. [PubMed: 2537655] [Full Text: https://doi.org/10.1016/0167-4781(89)90040-7]
Taira, M., Ishijima, S., Kita, K., Yamada, K., Iizasa, T., Tatibana, M. Nucleotide and deduced amino acid sequences of two distinct cDNAs for rat phosphoribosylpyrophosphate synthetase. J. Biol. Chem. 262: 14867-14870, 1987. [PubMed: 2822704]
Taira, M., Kudoh, J., Minoshima, S., Iizasa, T., Shimada, H., Shimizu, Y., Tatibana, M., Shimizu, N. Localization of human phosphoribosylpyrophosphate synthetase subunit I and II genes (PRPS1 and PRPS2) to different regions of the X chromosome and assignment of two PRPS1-related genes to autosomes. Somat. Cell Molec. Genet. 15: 29-37, 1989. [PubMed: 2536962] [Full Text: https://doi.org/10.1007/BF01534667]
Wang, J. C., Passage, M. B., Ellison, J., Becker, M. A., Yen, P. H., Shapiro, L. J., Mohandas, T. K. Physical mapping of loci in the distal half of the short arm of the human X chromosome: implications for the spreading of X-chromosome inactivation. Somat. Cell Molec. Genet. 18: 195-200, 1992. [PubMed: 1315458] [Full Text: https://doi.org/10.1007/BF01233165]