Sperm aster formation and pronuclear decondensation during rabbit fertilization and development of a functional assay for human sperm.
Human sperm aster formation and pronuclei decondensation in bovine eggs following intracytoplasmic sperm injection using a Piezo-Driven Pipette: a novel assay for human sperm centrosome formation.
The stages at which fertilization arrests in humans, defective sperm centrosomes and sperm asters as causes of human infertility.
A diminutive sperm aster was associated with the sperm nucleus during its decondensation, but no obvious extension toward the female pronucleus was observed.
Movement of the sperm nucleus, or subsequent pronucleus, through the egg cortex in most invertebrate and mammalian systems is attributed primarily to the formation of a microtubule-containing sperm aster.
At the same time, or immediately afterward, a small sperm aster started to develop (Fig.
In contrast, the sperm aster is significantly larger in most invertebrate and mammalian systems and is believed to be responsible for the migration of the male and female pronuclei during syngamy.
Finally, Schatten and Schatten (1981) reported that MT inhibitors increased the lateral displacement of the sperm head along the cortex and that the formation of the sperm aster may signal the end of this lateral movement (Schatten, 1982).
The last movement typically associated with flagellar bending occurs shortly after sperm binding, and movement of the sperm nucleus once inside the egg is typically associated with cytoskeletal elements, specifically the sperm aster (Schatten, 1982; Longo, 1987).