Increased expression of pro-inflammatory cytokines at the fetal-maternal interface in bovine pregnancies produced by cloning.

Problem: A significant rate of spontaneous abortion is observed in cattle pregnancies produced by somatic cell nuclear transfer (SCNT). Major histocompatibility complex class I (MHC-I) proteins are abnormally expressed on the surface of trophoblast cells from SCNT conceptuses.

Method Of Study: MHC-I homozygous compatible (n = 9), homozygous incompatible (n = 8), and heterozygous incompatible (n = 5) pregnancies were established by SCNT.

Trophoblast Major Histocompatibility Complex Class I Expression Is Associated with Immune-Mediated Rejection of Bovine Fetuses Produced by Cloning.

Trophoblast cells from bovine somatic cell nuclear transfer (SCNT) conceptuses express major histocompatibility complex class I (MHC-I) proteins early in gestation, and this may be one cause of the significant first-trimester embryonic mortality observed in these pregnancies. MHC-I homozygous-compatible (n = 9), homozygous-incompatible (n = 8), and heterozygous-incompatible (n = 5) SCNT pregnancies were established. The control group consisted of eight pregnancies produced by artificial insemination.

Abnormal levels of transcript abundance of developmentally important genes in various stages of preimplantation bovine somatic cell nuclear transfer embryos.

Based on microarray data comparing gene expression of fibroblast donor cells and bovine somatic cell nuclear transfer (SCNT) and in vivo produced (AI) blastocysts, a group of genes including several transcription factors was selected for evaluation of transcript abundance. Using SYBR green-based real-time polymerase chain reaction (Q-PCR) the levels of POU domain class 5 transcription factor (Oct4), snail homolog 2 (Snai2), annexin A1 (Anxa1), thrombospondin (Thbs), tumor-associated calcium signal transducer 1 (Tacstd1), and transcription factor AP2 gamma (Tfap2c) were evaluated in bovine fibroblasts, oocytes, embryos 30 min postfusion (SCNT), 12 h postfertilization/activation, as well as two-cell, four-cell, eight-cell, morula, and blastocyst-stage in vitro fertilized (IVF) and SCNT embryos. For every gene except Oct4, levels of transcript were indistinguishable between IVF and SCNT embryos at the blastocyst stage; however, in many cases levels of these genes during stages prior to blastocyst differed significantly.

Genetic reprogramming of transcription factor ap-2gamma in bovine somatic cell nuclear transfer preimplantation embryos and placentomes.

Bovine somatic cell nuclear transfer (SCNT) efficiency remains very low despite a tremendous amount of research devoted to its improvement over the past decade. Frequent early and mid-gestational losses are commonly accompanied by placental abnormalities. A transcription factor, activating protein AP-2gamma, has been shown to be necessary for proper placental development in the mouse.

The developmental competence of bovine nuclear transfer embryos derived from cow versus heifer cytoplasts.

Due to its economic importance, the production of cattle by nuclear transfer has been a primary research focus for many researchers during the past few years. While many groups have successfully produced cattle by nuclear transfer, and progress in this area continues, nuclear transfer remains a very inefficient technology. This study evaluates the effect of the oocyte source (cow and heifer) on the developmental competence of nuclear transfer embryos.