HGNC Approved Gene Symbol: SPESP1
Cytogenetic location: 15q23 Genomic coordinates (GRCh38): 15:68,930,525-68,946,811 (from NCBI)
Using a PCR-based probe to screen a human testis cDNA library, Wolkowicz et al. (2003) identified a novel cDNA, designated SPESP1, encoding a deduced 350-amino acid protein. The concanavalin-A-binding protein, which the authors designated equatorial segment protein (ESP), has a predicted molecular mass of 37 kD after cleavage of a putative 19-amino acid signal peptide, and 39.6 kD prior to this posttranslational modification. The protein contains a consensus N-glycosylation site and numerous cAMP-dependent kinase, protein kinase C, and casein kinase II consensus phosphorylation sites. Northern blot analysis revealed an approximately 1.4-kb transcript only in testis. RNA dot-blot analysis confirmed expression in testis but also showed faint signals for placenta and fetal lung. Western blot analysis indicated considerable heterogeneity of posttranslationally modified forms of SPESP1.
Using immunofluorescence and immunoelectron microscopy, Wolkowicz et al. (2003) demonstrated that SPESP1 localizes to the equatorial segment of human sperm early in development and defines a distinct equatorial segment subcompartment throughout acrosomal biogenesis.
Wolkowicz et al. (2003) determined that the SPESP1 gene contains 2 exons.
By sequence analysis, Wolkowicz et al. (2003) mapped the SPESP1 gene to chromosome 15q22.
Wolkowicz, M. J., Shetty, J., Westbrook, A., Klotz, K., Jayes, F., Mandal, A., Flickinger, C. J., Herr, J. C. Equatorial segment protein defines a discrete acrosomal subcompartment persisting throughout acrosomal biogenesis. Biol. Reprod. 69: 735-745, 2003. [PubMed: 12773409] [Full Text: https://doi.org/10.1095/biolreprod.103.016675]