Our group and others have found that the treatment of embryos with trichostatin A (TSA) after cloning by somatic cell nuclear transfer (SCNT) results in a significant improvement in efficiency. We believe that TSA treatment improves nuclear remodeling via histone modifications, which are important in the epigenetic regulation of gene silencing and expression. Some studies found that treatment of SCNT-generated embryos with TSA improved lysine acetylation of core histones in a manner similar to that seen in normally fertilized embryos. However, how histone methylation is modified in TSA-treated cloned embryos is not completely understood. In the present study, we found that TSA treatment caused an increase in chromosome decondensation and nuclear volume in SCNT-generated embryos similar to that in embryos produced by intracytoplasmic sperm injection. Histone acetylation increased in parallel with chromosome decondensation. This was associated with a more effective formation of DNA replication complexes in treated embryos. We also found a differential effect of TSA on the methylation of histone H3 at positions K4 and K9 in SCNT-generated embryos that could contribute to genomic reprogramming of the somatic cell nuclei. In addition, using 5-bromouridine 5'-triphosphate-labeled RNA, we showed that TSA enhanced the levels of newly synthesized RNA in 2-cell embryos. Interestingly, the amount of SCNT-generated embryos showing asymmetric expression of nascent RNA was reduced significantly in the TSA-treated group compared with the nontreated group at the 2-cell stage. We conclude that the incomplete and inaccurate genomic reprogramming of SCNT-generated embryos was improved by TSA treatment. This could enhance the reprogramming of somatic nuclei in terms of chromatin remodeling, histone modifications, DNA replication, and transcriptional activity.
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http://dx.doi.org/10.1095/biolreprod.109.083337 | DOI Listing |
Theriogenology
July 2020
RIKEN BioResource Research Center, Ibaraki, 305-0074, Japan; Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572, Japan; RIKEN Cluster for Pioneering Research, Saitama, 351-0198, Japan. Electronic address:
The mouse is the most extensively used mammalian laboratory species in biology and medicine because of the ready availability of a wide variety of defined genetic and gene-modified strains and abundant genetic information. Its small size and rapid generation turnover are also advantages compared with other experimental animals. Using these advantages, somatic cell nuclear transfer (SCNT) in mice has provided invaluable information on epigenetics related to SCNT technology and cloning, playing a leading role in relevant technical improvements.
View Article and Find Full Text PDFReprod Fertil Dev
June 2018
Department of Animal, Dairy and Veterinary Sciences, Utah State University, 4815 Old Main Hill, Logan, UT 84322, USA.
The hypothesis of this study was that the leukocyte populations and expression levels of genes related to immune response, growth factors and apoptosis would be altered at the fetal-maternal interface in somatic cell nuclear transfer (SCNT)-generated sheep pregnancies. Placental and endometrial samples from sheep pregnancies established by SCNT and natural breeding (control) were collected at 45 days and at term. Expression of genes related to growth factors, apoptosis and immune response was examined using quantitative reverse transcription polymerase chain reaction.
View Article and Find Full Text PDFCell Reprogram
December 2014
AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand .
Public perception of somatic cell nuclear transfer (SCNT) in the production of agricultural animals is surrounded by fear, which is exacerbated by the inability to differentiate animals generated by SCNT from those generated by natural mating or artificial insemination (AI). Unfortunately, the DNA sequence of animals produced by SCNT is indistinguishable from those generated by fertilization. With the current banning of all SCNT animal products from entering the food supply in some countries, the lack of a diagnostic test to identify SCNT animals may jeopardize market access for producers.
View Article and Find Full Text PDFPLoS One
August 2014
RIKEN BioResouce Center, Tsukuba, Ibaraki, Japan.
The great majority of embryos generated by somatic cell nuclear transfer (SCNT) display defined abnormal phenotypes after implantation, such as an increased likelihood of death and abnormal placentation. To gain better insight into the underlying mechanisms, we analyzed genome-wide gene expression profiles of day 6.5 postimplantation mouse embryos cloned from three different cell types (cumulus cells, neonatal Sertoli cells and fibroblasts).
View Article and Find Full Text PDFDevelopment
December 2012
Department of Animal Biotechnology, College of Animal Bioscience and Biotechnology/Animal Resources Research Center, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
Genomic reprogramming factors in the cytoplasm of germinal vesicle (GV) stage oocytes have been shown to improve the efficiency of producing cloned mouse offspring through the exposure of nuclei to a GV cytoplasmic extract prior to somatic cell nuclear transfer (SCNT) to enucleated oocytes. Here, we developed an extract of GV stage pig oocytes (GVcyto-extract) to investigate epigenetic reprogramming events in treated somatic cell nuclei. This extract induced differentiation-associated changes in fibroblasts, resulting in cells that exhibit pluripotent stem cell-like characteristics and that redifferentiate into three primary germ cell layers both in vivo and in vitro.
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