Alternative titles; symbols
HGNC Approved Gene Symbol: YBX2
Cytogenetic location: 17p13.1 Genomic coordinates (GRCh38): 17:7,288,263-7,294,639 (from NCBI)
YBX2 is a germ-cell specific member of the vertebrate Y box family of nucleic acid-binding proteins (Gu et al., 1998; Tekur et al., 1999).
By screening human testis cDNA libraries with mouse Ybx2, followed by rescreening with 5-prime oligonucleotides from positive clones, Tekur et al. (1999) cloned YBX2, which they called contrin. The deduced 364-amino acid protein has a calculated molecular mass of 38.6 kD and is arginine- and proline-rich. It shares 69% and 73% amino acid identity with DBPA (CSDA; 603437) and YB1 (NSEP1; 154030), respectively, and contains an N-terminal cold-shock domain (CSD), 7 putative phosphorylation sites for casein kinase II (see CSNK2A1; 115440), 3 potential phosphorylation sites for protein kinase C, and 2 nuclear localization signals within a B/A island. Northern blot analysis detected a 1.8-kb transcript in human testes only. YBX2 shares 93% and 77% amino acid identity with mouse Ybx2 and Xenopus Frgy2, respectively.
Gu et al. (1998) cloned mouse Ybx2, which they called Msy2, and an alternatively spliced isoform, Msy2a. The deduced 360-amino acid mouse Msy2 and 282-amino acid Msy2a isoforms have calculated molecular masses of 38 and 31 kD, respectively. Northern blot analysis of mouse tissues detected Msy2 in mouse germ cells only with expression first detected in testes from 12-day-old mice, increasing significantly by 17 days, and reaching maximal levels in 22-day-old mouse testes and persisting into adulthood. Western blot analysis and immunohistochemical studies detected Msy2 protein in mouse testes and in diplotene-stage and mature oocytes. By SDS-PAGE, they showed that mouse Msy2 and Msy2a isoforms migrated at molecular masses of 52 and 48 kD, respectively. This disparity in migration relative to its true molecular mass is a feature shared with other Y box proteins.
Using immunohistochemical studies, Kohno et al. (2006) detected highest DBPC levels in oocytes, spermatogonia, and spermatocytes with moderate expression in trophoblasts and low levels in lung, heart, adrenal cortex, and skeletal muscle. In contrast to the restricted distribution in normal cells, they found upregulated DBPC levels in a variety of human carcinomas, including adenocarcinomas of the colon (9/10) and cholangiocellular carcinomas (8/10). All germ cell tumors tested, including testicular seminomas and ovarian dysgerminomas, showed high DBPC levels by immunohistochemical analysis.
By PCR analysis with human-rodent somatic cell hybrids, Tekur et al. (1999) mapped the YBX2 gene to chromosome 17p13.1-p11.2.
Gu, W., Tekur, S., Reinbold, R., Eppig, J. J., Choi, Y.-C., Zheng, J. Z., Murray, M. T., Hecht, N. B. Mammalian male and female germ cells express a germ cell-specific Y-box protein, MSY2. Biol. Reprod. 59: 1266-1274, 1998. [PubMed: 9780336] [Full Text: https://doi.org/10.1095/biolreprod59.5.1266]
Kohno, Y., Matsuki, Y., Tanimoto, A., Izumi, H., Uchiumi, T., Kohno, K., Shimajiri, S., Sasaguri, Y. Expression of Y-box-binding protein dbpC/contrin, a potentially new cancer/testis antigen. Brit. J. Cancer 94: 710-716, 2006. [PubMed: 16479255] [Full Text: https://doi.org/10.1038/sj.bjc.6602987]
Tekur, S., Pawlak, A., Guellaen, G., Hecht, N. B. Contrin, the human homologue of a germ-cell Y-box-binding protein: cloning, expression, and chromosomal localization. J. Androl. 20: 135-144, 1999. [PubMed: 10100484]