Disease relevance of BND

• The functional domain structure of bindin, an adhesive protein component of the acrosomal granule of sea urchin sperm, has been analyzed using a series of carboxyl- and amino-terminal deletion analogs of recombinant bindin expressed in Escherichia coli [1].

High impact information on BND

• Recombinant protein corresponding to the species-specific EBR repeat displays species-specific sperm adhesion and bindin-binding activity [2].
• We report the isolation and sequence of bindin cDNA clones prepared from Strongylocentrotus purpuratus testis RNA [3].
• Bindin, a major protein of the sea urchin acrosome granule, mediates the species-specific adhesion and binding of sperm to egg required to effect fertilization [3].
• These results demonstrate that a few specific regions of the bindin molecule are involved in the sperm-egg contact and that certain of these regions mediate the species specificity of the interaction in a sequence-specific manner [4].
• Active peptides representing certain specific subregions of the bindin sequence displayed IC50 values < 10% of the average value for control peptides, and the IC50 for the most potent of the peptides tested was only approximately 1% of the control peptide value (IC50 = 2.2 microM) [4].

Biological context of BND

• Complementary to ongoing functional biochemical studies, I take a comparative approach to explore the molecular evolution of bindin in a group of closely related free-spawning echinoid species [5].
• The binding of fucoidan to bindin is stable in high salt (50% at 1.2 M NaCl) whereas the binding of fucoidan to DEAE-cellulose or polylysine is inhibited by the concentrations of salt normally found in sea water (50% at 0.2 and 0.5 M NaCl, respectively) [6].
• Thus, mode of bindin evolution is not correlated with phylogenetic affinities or molecular structure, but rather with whether the species in a genus are allopatric or sympatric [7].
• Bindin, a sea urchin sperm protein, mediates sperm-egg attachment and membrane fusion and is thus important in species recognition and speciation [7].
• Two new bindin cDNA sequences that contain the entire open reading frame for the binding precursor are reported: one for Strongylocentrotus franciscanus and one for Lytechinus variegatus [8].

Anatomical context of BND

• The bindin gene appears to be productively expressed only in males and only in testes [3].
• We correlate the number of bindin mRNA molecules with morphological structure and with quantitative aspects of gonad maturation including the number of nuclei and of sperm [9].
• Bindin message accumulates in late spermatocytes and early spermatids which lie in the luminal germinal layer [9].
• Bindin is a sperm recognition protein that mediates species-specific gamete interactions in sea urchins [10].
• A precipitate of this DEAE-purified bindin, made by dialysis into Ca2+-free seawater and natural seawater, is a species-specific agglutinin of unfertilized eggs [11].

Associations of BND with chemical compounds

• Polysaccharide structural features that are critical for the binding of sulfated fucans to bindin, the adhesive protein from sea urchin sperm [6].
• The data presented demonstrate that the sulfate esters and a molecular weight in excess of approximately 15,000 are required for high affinity binding of the fucans to bindin [6].
• We have investigated the structural features of sulfated fucose-containing polysaccharides which are responsible for their selective binding to Strongylocentrotus purpuratus bindin [6].
• Group-specific modification of either arginine, lysine, or histidine residues of bindin results in a substantial inactivation of fucan binding activity [12].
• Other sulfated polysaccharides which do not interact strongly with bindin did not protect binding from phenylglyoxal-mediated inactivation when 800-3000-fold more polysaccharide than fucan was used during the preincubation before modification [12].

Analytical, diagnostic and therapeutic context of BND

• We used PCR representation difference analysis to clone the species-specific egg receptor for bindin, EBR1, from Strongylocentrotus franciscanus (Sf) and S. purpuratus (Sp) [2].
• Species-specific inhibition of fertilization by a peptide derived from the sperm protein bindin [4].
• Immunogold labeling of ultrathin sections and electron microscopy reveal that this punctate immunofluorescence is an apparent result of localized deposits of bindin in intracellular vesicles [13].
• Purification of sea urchin sperm bindin by DEAE-cellulose chromatography [11].
• In situ hybridization studies, using an 35S-labeled antisense RNA probe transcribed from a bindin cDNA, reveal that bindin mRNAs are localized in spermatogenic cells displaced towards the lumens of maturing testicular acini [13].

References