a1 Department of Animal Sciences, Chungbuk National University, Cheongju, Chungbuk 361–763, South Korea.
a2 Department of Animal Sciences, Chungbuk National University, Cheongju, Chungbuk 361–763, South Korea.
a3 Laboratory Animal Center, Jilin University, Changchun, Jilin Province, 130062, China.
a4 Division of Applied Life Science, Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, GyeongNam, South Korea.
Interspecies intracytoplasmic sperm injection has been carried out to understand species-specific differences in oocyte environments and sperm components during fertilization. While sperm aster organization during cat fertilization requires a paternally derived centriole, mouse and hamster fertilization occur within the maternal centrosomal components. To address the questions of where sperm aster assembly occurs and whether complete fertilization is achieved in cat oocytes by interspecies sperm, we studied the fertilization processes of cat oocytes following the injection of cat, mouse, or hamster sperm. Male and female pronuclear formations were not different in the cat oocytes at 6 h following cat, mouse or hamster sperm injection. Microtubule asters were seen in all oocytes following intracytoplasmic injection of cat, mouse or hamster sperm. Immunocytochemical staining with a histone H3-m2K9 antibody revealed that mouse sperm chromatin is incorporated normally with cat egg chromatin, and that the cat eggs fertilized with mouse sperm enter metaphase and become normal 2-cell stage embryos. These results suggest that sperm aster formation is maternally dependent, and that fertilization processes and cleavage occur in a non-species specific manner in cat oocytes.
(Received June 10 2011)
(Accepted June 13 2011)
(Online publication July 27 2011)
c1 All correspondence to: Nam-Hyung Kim. Department of Animal Sciences, Chungbuk National University, Cheongju, Chungbuk 361–763, South Korea. Tel: +82 43 261 2546. Fax: +82 43 272 8853. E-mail: firstname.lastname@example.org