Submitted on September 25, 2007
Accepted on December 11, 2007
Aberrant gene expression patterns in placentomes are associated with phenotypically normal and abnormal cattle cloned by somatic cell nuclear transfer
Robin E Everts1, Pascale Chavatte-Palmer2, Anthony Razzak1, Isabelle Hue2, Cheryl A Green1, Rosane Oliveira1, Xavier Vignon2, Sandra L. Rodriguez-Zas1, X. Cindy Tian3, Xiangzhong Yang3, Jean-Paul Renard2, and Harris A. Lewin4*
1 Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
2 UMR Biologie du Developpement et Reproduction, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
3 Animal Sciences, University of Connecticut, Storrs, Connecticut, United States
4 Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States; Institute for Genomic Biology, Univ. of Illinois, Urbana, Illinois, United States
* To whom correspondence should be addressed. E-mail: h-lewin{at}uiuc.edu.
Transcription profiling of placentomes derived from somatic cell nuclear transfer (SCNT, N=20), in vitro fertilization (IVF, N=9) and artificial insemination (AI, N=9) was performed to better understand why SCNT and IVF often result in placental defects, hydrops and large offspring syndrome (LOS). Multivariate analysis of variance was used to distinguish the effects of SCNT, IVF and AI on gene expression, taking into account the effects of parturition, sex of the fetus, breed of dam, breed of fetus and pathological finding in the offspring (hydrops, normal). The differential expression of 20 genes was confirmed using quantitative PCR. The largest effect on placentome gene expression was attributable to whether placentae were collected at term or preterm followed by placentome source. Gene expression in SCNT placentomes was dramatically different from AI (N=336 genes) and from IVF (N=733 genes) placentomes. Functional analysis of differentially expressed genes (DEG) showed that IVF has significant effects on genes associated with cellular metabolism. In contrast, DEG associated with SCNT are involved in multiple pathways, including cell cycle and others listed in Table 2 and Suppl. Table 5. Many DEG were shared between the gene lists for IVF and SCNT comparisons, suggesting that common pathways are affected by the embryo culture methods used for IVF and SCNT. However, the many unique gene functions and pathways affected by SCNT suggest that cloned fetuses may be starved and accumulating toxic wastes due to placental insufficiency caused by reprogramming errors. Many of these genes are candidates for hydrops and LOS.
