Transcriptional reprogramming of gene expression in bovine somatic cell chromatin transfer embryos.
BACKGROUND
Successful reprogramming of a somatic genome to produce a healthy clone by somatic cells nuclear transfer (SCNT) is a rare event and the mechanisms involved in this process are poorly defined. When serial or successive rounds of cloning are performed, blastocyst and full term development rates decline even further with the increasing rounds of cloning. Identifying the "cumulative errors" could reveal the epigenetic reprogramming blocks in animal cloning.


RESULTS
Bovine clones from up to four generations of successive cloning were produced by chromatin transfer (CT). Using Affymetrix bovine microarrays we determined that the transcriptomes of blastocysts derived from the first and the fourth rounds of cloning (CT1 and CT4 respectively) have undergone an extensive reprogramming and were more similar to blastocysts derived from in vitro fertilization (IVF) than to the donor cells used for the first and the fourth rounds of chromatin transfer (DC1 and DC4 respectively). However a set of transcripts in the cloned embryos showed a misregulated pattern when compared to IVF embryos. Among the genes consistently upregulated in both CT groups compared to the IVF embryos were genes involved in regulation of cytoskeleton and cell shape. Among the genes consistently upregulated in IVF embryos compared to both CT groups were genes involved in chromatin remodelling and stress coping.


CONCLUSIONS
The present study provides a data set that could contribute in our understanding of epigenetic errors in somatic cell chromatin transfer. Identifying "cumulative errors" after serial cloning could reveal some of the epigenetic reprogramming blocks shedding light on the reprogramming process, important for both basic and applied research.
Rodriguez-Osorio
Nelida
N
Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS, USA. nerodriguez@agronica.udea.edu.co
Wang
Zhongde
Z
Kasinathan
Poothappillai
P
Page
Grier P
GP
Robl
James M
JM
Memili
Erdogan
E
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002417:Cattle / Q000196:embryology / Q000235:genetics*; D002460:Cell Line; D065150:Cellular Reprogramming; D019976:Cloning, Organism; D016000:Cluster Analysis; D004622:Embryo, Mammalian / Q000378:metabolism; D044127:Epigenesis, Genetic; D005307:Fertilization in Vitro; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D053652:Nuclear Transfer Techniques; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction