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Zonadhesin D3-Polypeptides Vary among Species but Are Similar in Equus Species Capable of Interbreeding1

Authors :
Daniel M. Hardy
Steve Tardif
Jason E. Bruemmer
Laura B. Bailey
H.A. Brady
Kelly R. Breazeale
Ming Bi
Leslie D. Thompson
Source :
Biology of Reproduction. 82:413-421
Publication Year :
2010
Publisher :
Oxford University Press (OUP), 2010.

Abstract

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acrosomes of spermatozoa from all three Equus species, similar to its localization in other animals. Likewise, in horse and donkey testis, zonadhesin was detected only in germ cells, first in the acrosomal granule of round spermatids and then in the developing acrosomes of elongating spermatids. Among non-Equus species, D3-domain polypeptides of mature, processed zonadhesin varied markedly in size and detergent solubility. However, zonadhesin D3-domain polypeptides in horse, donkey, and zebra spermatozoa exhibited identical electrophoretic mobility and detergent solubility. Equus zonadhesin D3-polypeptides (p110/p80 doublet) were most similar in size to porcine and bovine zonadhesin D3-polypeptides (p105). Sequence comparisons revealed that the horse zonadhesin precursor's domain content and arrangement are similar to those of zonadhesin from other large animals. Partial sequences of horse and donkey zonadhesin were much more similar to each other (>99% identity) than they were to orthologous sequences of human, pig, rabbit, and mouse zonadhesin (52%–72% identity). We conclude that conservation of zonadhesin D3-polypeptide properties correlates with ability of Equus species to interbreed.

Details

ISSN :
15297268 and 00063363
Volume :
82
Database :
OpenAIRE
Journal :
Biology of Reproduction
Accession number :
edsair.doi...........a6630d0cc4082caabadeb55e38b9d4d4
Full Text :
https://doi.org/10.1095/biolreprod.109.077891