Extraordinary divergence and positive Darwinian selection in a fusagenic protein coating the acrosomal process of abalone spermatozoa. Export

@article{citeulike:656285, abstract = {During fertilization in marine invertebrates, fusion between sperm and egg cell membranes occurs at the tip of the sperm acrosomal process. In abalone sperm the acrosomal process is coated with an 18-kDa protein. In situ, this protein has no effect on the egg vitelline envelope, but in vitro it is a potent fusagen of liposomes. Thus, the 18-kDa protein may mediate membrane fusion between the gametes, a step in gamete recognition known to restrict heterospecific fertilization in other species. The cDNA and deduced amino acid sequences of the 18-kDa protein were determined for five species of California abalone. The deduced amino acid sequences exhibit extraordinary divergence; the percent identity varies from 27\% to 87\%. Analysis of nucleotide substitution shows extremely high frequencies of amino acid-altering substitution compared to silent substitution, demonstrating that positive Darwinian selection promotes the divergence of this protein. However, amino acid replacement is conservative with respect to size and polarity of residue. The data support the developing idea that in free-spawning marine invertebrates, the proteins mediating fertilization may be subjected to intense, and as yet unknown, selective forces. The extraordinary divergence of fertilization proteins may be related to the establishment of barriers to heterospecific fertilization.}, address = {Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093-0202, USA.}, author = {Swanson, W. J. and Vacquier, V. D.}, citeulike-article-id = {656285}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/7761431}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=7761431}, day = {23}, issn = {0027-8424}, journal = {Proc Natl Acad Sci U S A}, keywords = {-abalone, acrosome, gamete\_recognition, selection}, month = {May}, number = {11}, pages = {4957--4961}, posted-at = {2006-05-19 01:25:29}, priority = {2}, title = {Extraordinary divergence and positive Darwinian selection in a fusagenic protein coating the acrosomal process of abalone spermatozoa.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/7761431}, volume = {92}, year = {1995} }

TY - JOUR ID - citeulike:656285 L3 - citeulike-article-id:656285 N2 - During fertilization in marine invertebrates, fusion between sperm and egg cell membranes occurs at the tip of the sperm acrosomal process. In abalone sperm the acrosomal process is coated with an 18-kDa protein. In situ, this protein has no effect on the egg vitelline envelope, but in vitro it is a potent fusagen of liposomes. Thus, the 18-kDa protein may mediate membrane fusion between the gametes, a step in gamete recognition known to restrict heterospecific fertilization in other species. The cDNA and deduced amino acid sequences of the 18-kDa protein were determined for five species of California abalone. The deduced amino acid sequences exhibit extraordinary divergence; the percent identity varies from 27% to 87%. Analysis of nucleotide substitution shows extremely high frequencies of amino acid-altering substitution compared to silent substitution, demonstrating that positive Darwinian selection promotes the divergence of this protein. However, amino acid replacement is conservative with respect to size and polarity of residue. The data support the developing idea that in free-spawning marine invertebrates, the proteins mediating fertilization may be subjected to intense, and as yet unknown, selective forces. The extraordinary divergence of fertilization proteins may be related to the establishment of barriers to heterospecific fertilization. IS - 11 JF - Proc Natl Acad Sci U S A SN - 0027-8424 AD - Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093-0202, USA. EP - 4961 TI - Extraordinary divergence and positive Darwinian selection in a fusagenic protein coating the acrosomal process of abalone spermatozoa. VL - 92 SP - 4957 KW - -abalone KW - acrosome KW - gamete_recognition KW - selection AU - Swanson, WJ AU - Vacquier, VD PY - 1995/05/23/ UR - http://view.ncbi.nlm.nih.gov/pubmed/7761431 ER -