Expression of imprinted genes is aberrant in deceased newborn cloned calves and relatively normal in surviving adult clones.
Cattle are the species used most frequently for the development of assisted reproductive technologies, such as nuclear transfer. Cattle cloning can be performed by a large number of laboratories around the world, and the efficiency of nuclear transfer in cattle is the highest among all species in which successful cloning has been achieved. However, an understanding of the expression of imprinted genes in this important species is lacking. In the present study, real time reverse transcription polymerase chain reaction (RT-PCR) was utilized to quantify the expression of the bovine Igf2, Igf2r, and H19 genes in eight major organs (brain, bladder, heart, kidney, liver, lung, spleen, and thymus) of somatic cell cloned calves that died shortly after birth, in three tissues (skin, muscle, and liver) of healthy clones that survived to adulthood, and in corresponding tissues of control animals from natural reproduction. We found that, deceased bovine cloned calves exhibited abnormal expression of all three genes studied in various organs. Large variations in the expression levels of imprinted genes were also seen among these clones, which were produced from the same genetic donor. In surviving adult clones, however, the expression of these imprinted genes was largely normal, except for the expression of the Igf2 gene in muscle, which was highly variable. Our data showed disruptions of expression of imprinted genes in bovine clones, which is possibly due to incomplete reprogramming of donor cell nuclei during nuclear transfer, and these abnormalities may be associated with the high neonatal mortality in cloned animals; clones that survived to adulthood, however, are not only physically healthy but also relatively normal at the molecular level of those three imprinted genes.
Yang
Lan
L
Department of Animal Science and Center for Regenerative Biology, University of Connecticut, Storrs, Connecticut 06269-4243, USA.
Chavatte-Palmer
Pascale
P
Kubota
Chikara
C
O'neill
Michael
M
Hoagland
Thomas
T
Renard
Jean-Paul
JP
Taneja
Maneesh
M
Yang
Xiangzhong
X
Tian
X Cindy
XC
D000818:Animals; D052160:Benzothiazoles; D001724:Birth Weight; D002417:Cattle; D019976:Cloning, Organism; D003959:Diamines; D005260:Female; D018392:Genomic Imprinting; D007335:Insulin-Like Growth Factor II; D019656:Loss of Heterozygosity; D009930:Organic Chemicals; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011804:Quinolines; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D017527:Receptor, IGF Type 2 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D052160:Benzothiazoles; D003959:Diamines; C094335:H19 long non-coding RNA; C035170:IGF2 protein, human; D009930:Organic Chemicals; D011506:Proteins; D011804:Quinolines; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D017527:Receptor, IGF Type 2; C098022:SYBR Green I; D007335:Insulin-Like Growth Factor II