title: Effect of oocyte mitochondrial DNA haplotype on bovine somatic cell nuclear transfer efficiency.
abstract: The development capability of reconstructed bovine embryos via ovum pick-up (OPU)-somatic cell nuclear transfer (SCNT) technique has been influenced by the maternal lineage of oocyte cytoplasm, but the underlying mechanism remains unclear. Since mitochondria are the richest maternal-inherited organelle, in this study, we intended to clarify the effect of mtDNA haplotypes on cloning efficiency. By PCR-RFLP method, we identified mtDNA haplotypes A and B, differing in six restriction sites. Reconstructed embryos with haplotype A cytoplast achieved better fusion and blastocyst formation rate (64.6% and 39.4%), as compared with haplotype B (53.6% and 26.3%; P < 0.05). To further evaluate the role of mitochondria, the quantity of mtDNA, ATP content, and mRNA level of mtDNA-encoded COXI, COXIII in both oocytes were measured. Our data indicated that mtDNA copy number in haplotype A oocyte was significantly higher than that in haplotype B oocyte, both at the GV (10(5.03 +/- 0.69) vs. 10(4.81 +/- 0.86) copies/oocyte) and MII stages (10(5.31 +/- 0.71) vs. 10(5.13 +/- 0.63) copies/oocyte; logarithmically transformed values; P < 0.05). ATP content in type A oocyte was also greater at the GV (1.67 +/- 0.09 vs. 1.27 +/- 0.1 pmol) and MII stages (5.18 +/- 0.07 vs. 2.68 +/- 0.03 pmol; P < 0.05). Similarly, the mRNA expression level of mtDNA-encoded COXI and COXIII in haplotype A oocyte was significantly higher comparing to haplotype B oocyte (3.3 +/- 2.0 x 10(3) vs. 0.68 +/- 0.45 x 10(3); 24.9 +/- 10.5 x 10(3) vs. 9.4 +/- 3.3 x 10(3), respectively; P < 0.05). The data suggest that mitochondrial structure, quantity, and function may significantly affect the developmental competence of reconstructed embryos.
authors.affiliation: Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Jiao
authors.forename: Jing-Bin
authors.initials: JB
authors.lastname: Yan
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Qingxue
authors.initials: Q
authors.lastname: Wang
authors.forename: Shu-Zhen
authors.initials: SZ
authors.lastname: Huang
authors.forename: Fanyi
authors.initials: F
authors.lastname: Zeng
authors.forename: Yi-Tao
authors.initials: YT
authors.lastname: Zeng
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D002417:Cattle; D004272:DNA, Mitochondrial / Q000502:physiology*; D004526:Efficiency; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D006239:Haplotypes / Q000502:physiology*; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis / Q000235:genetics; D021122:Protein Subunits / Q000032:analysis / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D011451:Prostaglandin-Endoperoxide Synthases