After fertilization, sperm surface components remain as a patch in sea urchin and mouse embryos.
Sea urchin and mouse sperm that are labeled on their surfaces with fluorescein isothiocyanate (FITC), tetramethylrhodamine isothiocyanate (TMRTC) or 125I-diiodofluorescein isothiocyanate (125IFC) remain viable and can fertilize eggs. When sea urchin eggs were fertilized with 125IFC-labeled sperm, the radioactivity from the sperm was quantitatively transferred to the egg (at a ratio of one sperm equivalent per egg) and persisted in the embryo as it developed to the pluteus larval state (5 days at 12 degrees C). The radioactivity was acid-precipitable and was associated with the particulate fraction of embryo homogenates. In addition, FITC-labeled sea urchin sperm were used to fertilize eggs, and the labeled components were followed by fluorescence microscopy. In the embryo, labeled sperm components were present as a discrete patch that was partitioned unequally during early cleavages. In experiments using mouse sperm labeled with TMRTC, the labeled sperm components were also transferred to the embryo as a discrete patch that was again distributed unequally after cleavage. This physiological cell fusion system therefore has distinctive characteristics: there is limited lateral mobility of surface components, which have a low turnover rate unlike that see in other systems. In this paper, we discussed the possible morphogenetic role of this unusual behavior.
D000818:Animals; D004622:Embryo, Mammalian / Q000378:metabolism / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian; D005260:Female; D005306:Fertilization; D005452:Fluoresceins; D007457:Iodine Radioisotopes; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D011247:Pregnancy; D012617:Sea Urchins; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism / Q000648:ultrastructure*
D005452:Fluoresceins; D007457:Iodine Radioisotopes; D008565:Membrane Proteins