Experimental approach to prezygotic chromosome screening using only a single pair of gametes in
mice |
| |
Authors: | Hiroyuki WATANABE Atsushi KOHDA Hiroyuki TATENO |
| |
Institution: | 1)Department of Biological Sciences, Asahikawa Medical University, Hokkaido 078-8510, Japan;2)Department of Radiobiology, Institute for Environmental Sciences, Aomori 039-3213, Japan |
| |
Abstract: | During in vitro embryo production, chromosome screening is essential to prevent pregnancy
losses caused by embryonic chromosome aberrations. When the chromosome screening is completed before
fertilization, gametes are effectively utilized as genetic resources. The aim of this study was to investigate
whether chromosome screening of gametes accompanied by fertilization would be feasible using a single mouse
spermatozoon and oocyte. Metaphase II oocytes were divided into a cytoplast and a karyoplast. For genome
cloning of the gametes, androgenic and gynogenic embryos were produced by microinjection of sperm into
cytoplasts and parthenogenetic activation of karyoplasts, respectively. Pairs of blastomeres from androgenic
and gynogenic embryos were fused electrically to produce diploid embryos, which were transferred into
pseudopregnant surrogate mothers to examine fetal development. Blastomeres from androgenic and gynogenic
embryos were individually treated with calyculin A—a specific inhibitor of type 1 and 2A protein
phosphatases—for 2 h to induce premature chromosome condensation. Thereafter, chromosome analysis of
blastomeres, reflecting the genetic constitution of individual spermatozoa and oocytes, was performed, and we
confirmed that most of the androgenic and gynogenic 2-cell embryos had a haploid set of chromosomes in their
sister blastomeres. The reconstructed embryos from blastomeres of androgenic and gynogenic 2-cell embryos
could be implanted and develop into live fetuses, albeit at low efficiency. This study indicates that
prezygotic chromosome screening and embryo production using a single pair of gametes may be practicable. |
| |
Keywords: | Assisted reproductive technology Chromosome screening Gamete Genetic diagnosis Premature chromosome condensation |
|
|