Evolutionary diversification of SPANX-N sperm protein gene structure and expression.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Kouprina, Natalay; Noskov, Vladimir N; Pavlicek, Adam; Collins, N Keith; Schoppee Bortz, Pamela D; Ottolenghi, Chris; Loukinov, Dmitri; Goldsmith, Paul; Risinger, John I; Kim, Jung-Hyun; Westbrook, V Anne; Solomon, Gregory; Sounders, Hanna; Herr, John C; Jurka, Jerzy; Lobanenkov, Victor; Schlessinger, David; Larionov, Vladimir
Year of Publication: 2007
Journal: PLoS One
Volume: 2
Issue: 4
Pagination: e359
Date Published: 2007
Publication Language: eng
ISSN: 1932-6203
Keywords: Amino Acid Sequence, Animals, Antibody Specificity, Cell Line, Tumor, Chromosomes, Human, X, Electrophoretic Mobility Shift Assay, Evolution, Molecular, Fluorescent Antibody Technique, Fluorescent Antibody Technique, Indirect, Humans, Male, Molecular Sequence Data, Nuclear Proteins, Promoter Regions, Genetic, Recombinant Proteins, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid

The sperm protein associated with nucleus in the X chromosome (SPANX) genes cluster at Xq27 in two subfamilies, SPANX-A/D and SPANX-N. SPANX-A/D is specific for hominoids and is fairly well characterized. The SPANX-N gave rise to SPANX-A/D in the hominoid lineage approximately 7 MYA. Given the proposed role of SPANX genes in spermatogenesis, we have extended studies to SPANX-N gene evolution, variation, regulation of expression, and intra-sperm localization. By immunofluorescence analysis, SPANX-N proteins are localized in post-meiotic spermatids exclusively, like SPANX-A/D. But in contrast to SPANX-A/D, SPANX-N are found in all ejaculated spermatozoa rather than only in a subpopulation, are localized in the acrosome rather than in the nuclear envelope, and are expressed at a low level in several nongametogenic adult tissues as well as many cancers. Presence of a binding site for CTCF and its testis-specific paralogue BORIS in the SPANX promoters suggests, by analogy to MAGE-A1 and NY-ESO-1, that their activation in spermatogenesis is mediated by the programmed replacement of CTCF by BORIS. Based on the relative density of CpG, the more extended expression of SPANX-N compared to SPANX-A/D in nongametogenic tissues is likely attributed to differences in promoter methylation. Our findings suggest that the recent duplication of SPANX genes in hominoids was accompanied by different localization of SPANX-N proteins in post-meiotic sperm and additional expression in several nongonadal tissues. This suggests a corresponding functional diversification of SPANX gene families in hominoids. SPANX proteins thus provide unique targets to investigate their roles in the function of spermatozoa, selected malignancies, and for SPANX-N, in other tissues as well.

DOI: 10.1371/journal.pone.0000359
Alternate Journal: PLoS ONE
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