Microtubule distribution during fertilization in the rabbit

Abstract

The distribution of microtubules was studied during fertilization of the rabbit oocyte by immunofluorescence microscopy after staining with an anti-alpha-tubulin antibody. In ovulated oocytes, microtubules were found exclusively in the meiotic spindle. At fertilization, the paternal centrosome generated sperm astral microtubules. During pronuclear development, the sperm aster increased in size, and microtubules extended from the male pronucleus to the egg center and towards the female pronucleus. These observations indicate that microtubules emanating from the sperm centrosome were involved in the movements leading to the union of the male and female pronuclei. At late pronuclear stage, microtubules surrounded the adjacent pronuclei. The mitotic spindle that emerged from the perinuclear microtubules contained broad anastral poles.

Cytoskeletal Organization of Porcine Oocytes Aged and Activated Electrically or by Sperm.

“…The present results showed that the meiotic spindle of the porcine oocyte is peripherally located and radially oriented with its long axis as seen in other domestic species [6,8,10] and humans [16], and no rotation of the meiotic spindle occurred unlike in laboratory rodents [3,5]. Further, the meiotic spindle is barrel-shaped in the pig ( [11] and this study) and cattle [10], and is approximately 10 µm long, whereas in laboratory rodents it is much more elongated and tapered [5,23] with a length of 26.4 ± 0.3 µm in the mouse [23] and 16.4 ± 0.7 µm in the hamster (our unpublished observation).…”

“…Cytoskeleton organization is well known to be important for the progression of these events in mammals such as the mouse [1-4], rat [5], rabbit [6], sheep [7,8], cattle [9,10], pig [11][12][13][14][15] and human [16]. Our previous studies showed that cytoskeletal alteration is involved in the dynamic change of the cumulus-oocyte cell communication during oocyte maturation, and that the cumulus mass condition affects oocyte maturation in the pig [17,18].Observations of the early events of fertilization have indicated the paternal inheritance of a microtubule-organizing center in oocytes of rabbits [6], sheep [7], cattle [9], and pigs [12][13][14][15]19]. In pig oocytes, sperm aster enlarged during sperm decondensation and extended throughout the cytoplasm at the time of pronuclear apposition [12,13].…”

“…These include the resumption of meiosis, chromosome condensation, spindle formation, polar body emission, sperm incorporation and pronuclear formation and migration. Cytoskeleton organization is well known to be important for the progression of these events in mammals such as the mouse [1][2][3][4], rat [5], rabbit [6], sheep [7,8], cattle [9,10], pig [11][12][13][14][15] and human [16]. Our previous studies showed that cytoskeletal alteration is involved in the dynamic change of the cumulus-oocyte cell communication during oocyte maturation, and that the cumulus mass condition affects oocyte maturation in the pig [17,18].…”

“…Observations of the early events of fertilization have indicated the paternal inheritance of a microtubule-organizing center in oocytes of rabbits [6], sheep [7], cattle [9], and pigs [12][13][14][15]19]. In pig oocytes, sperm aster enlarged during sperm decondensation and extended throughout the cytoplasm at the time of pronuclear apposition [12,13].…”

Essential Roles of the Sperm Centrosome in Human Fertilization: Developing the Therapy for Fertilization Failure due to Sperm Centrosomal Dysfunction

“…The human sperm aster formation rate at 6 h post-ICSI is 36.1% in rabbit oocyte and 60.0% in bovine oocyte (Terada et al 2000;Terada et al 2004b). The microtubule organization in these systems is derived from the paternal centrosome during fertilization, and mimics that seen in normal human fertilization Yellera-Fernandez et al 1992;Navara et al 1994). In 2004, we reported human sperm aster formation rates in rabbit oocytes after heterologous microinjection, using sperm from infertile men.…”