Aberrant gene expression patterns in placentomes are associated with phenotypically normal and abnormal cattle cloned by somatic cell nuclear transfer.
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) at or near term development 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 (term or preterm), sex of fetus, breed of dam, breed of fetus, and pathological finding in the offspring (hydrops, normal, or other abnormalities). Differential expression of 20 physiologically important genes was confirmed with quantitative PCR. The largest effect on placentome gene expression was attributable to whether placentas were collected at term or preterm (i.e., whether the collection was because of disease or to obtain stage-matched controls) followed by placentome source (AI, IVF, or SCNT). Gene expression in SCNT placentomes was dramatically different from AI (n = 336 genes; 276 >2-fold) and from IVF (n = 733 genes; 162 >2-fold) 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, cell death, and gene expression. 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.
Everts
Robin E
RE
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Chavatte-Palmer
Pascale
P
Razzak
Anthony
A
Hue
Isabelle
I
Green
Cheryl A
CA
Oliveira
Rosane
R
Vignon
Xavier
X
Rodriguez-Zas
Sandra L
SL
Tian
X Cindy
XC
Yang
Xiangzhong
X
Renard
Jean-Paul
JP
Lewin
Harris A
HA
D000818:Animals; D002417:Cattle / Q000235:genetics*; D002478:Cells, Cultured; D019976:Cloning, Organism; D016000:Cluster Analysis; D004622:Embryo, Mammalian; D005260:Female; D005307:Fertilization in Vitro; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D053652:Nuclear Transfer Techniques; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy