Mol Reprod Dev 2005 Mar 01;703:344-60. doi: 10.1002/mrd.20201.

Allurin, a 21 kD sperm chemoattractant, is rapidly released from the outermost jelly layer of the Xenopus egg by diffusion and medium convection.

Abstract
Allurin, a 21 kD protein from Xenopus laevis egg jelly, has been demonstrated to attract sperm by video microscopy and by quantitative chemotaxis chamber assays. Here, we use immunocytochemistry to demonstrate that this sperm chemoattractant is located in the outermost layer of egg jelly (J3) and is rapidly released into the surrounding medium. SDS-PAGE analysis and Western blotting confirm the appearance of allurin in the medium within 1.5 min and separation of proteins in the medium by anion exchange FPLC, shows that nearly half of the allurin released over a 12-hr period is discharged in the first 5 min. The kinetics of allurin release from J3 and its appearance in the medium were quantitatively accounted for, by computer simulation of mathematical diffusion and convection models. Comparison of simulation data to quantitative measurements of allurin appearance in the medium suggests that allurin, although larger than most chemoattractants, is effectively dispersed by a combination of diffusion and medium mixing at the jelly surface during spawning. Our model further predicts that the innermost jelly layer, J1, is less permeable to allurin than the other layers, allowing it to act as a "reflector" to speed up allurin discharge.

PubMed ID: 15625699
Article link: Mol Reprod Dev


Species referenced: Xenopus laevis
Genes referenced: crisp3
Antibodies: Crisp3 Ab1 Crisp3 Ab2