Aberrant expression patterns of genes involved in segregation of inner cell mass and trophectoderm lineages in bovine embryos derived from somatic cell nuclear transfer.
High rates of embryonic, fetal, or placental abnormalities have consistently been observed in bovine cloning. Segregation of inner cell mass (ICM) and trophectoderm (TE) lineages in early embryos is an important process for fetal and placental formation. In mouse embryos, differentiation of ICM and TE is regulated by various transcription factors, such as OCT-4, CDX2, and TEAD4, but molecular mechanisms that regulate differentiation in bovine embryos remain unknown. To clarify gene transcripts involved in segregation of ICM and TE lineages in bovine embryos, we examined the relative abundances of OCT-4, CDX2, TEAD4, GATA3, NANOG, and FGF4 transcripts in blastocyst embryos derived from in vitro fertilization (IVF). Furthermore, transcript levels of such genes in bovine embryos derived from somatic cell nuclear transfer (NT-SC) and in vivo (Vivo) were also compared. OCT-4, NANOG, and FGF4 transcript levels in IVF embryos were significantly higher in ICM than in TE. In contrast, the CDX2 transcript level was lower in ICM than in TE. In NT-SC embryos at the blastocyst stage, transcript levels of all genes except CDX2 were lower than that in Vivo embryos. In the elongated stage, expression levels of the six genes did not differ between NT-SC and Vivo embryos. We observed aberrant expression patterns of various genes involved in segregation of ICM and TE lineages in bovine NT-SC embryos. These results raise the possibility that abnormalities in the cloned fetus and placenta are related to the aberrant expression of genes involved in segregation and differentiation process in the early developmental stage.
Fujii
Takashi
T
Iwate University, Japan.
Moriyasu
Satoru
S
Hirayama
Hiroki
H
Hashizume
Tsutomu
T
Sawai
Ken
K
D000818:Animals; D001483:Base Sequence; D053624:Blastocyst Inner Cell Mass / Q000378:metabolism*; D002417:Cattle; D019976:Cloning, Organism; D017931:DNA Primers / Q000235:genetics; D004475:Ectoderm / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005307:Fertilization in Vitro; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics; D066298:In Vitro Techniques; D051379:Mice; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014327:Trophoblasts / Q000378:metabolism
D017931:DNA Primers; D018398:Homeodomain Proteins; D050814:Octamer Transcription Factor-3; D012333:RNA, Messenger