Cloning by somatic nuclear transfer is an inefficient process in which many of the cloned ani- mals died shortly after birth and displayed organ ab- normalities. In an effort to determine the possible genetic causes o...Cloning by somatic nuclear transfer is an inefficient process in which many of the cloned ani- mals died shortly after birth and displayed organ ab- normalities. In an effort to determine the possible genetic causes of neonatal death and organ abnor- malities, we have examined expression patterns of four genes that modified chromatin (DNMT1, PCAF,MeCP2 and EED) in six organs (heart, liver, spleen, lung, kidney and brain) of both neonatal death cloned bovines (n=9) and normal control calves produced by artificial insemination (AI) using real-time quantitative RT-PCR. The effect of the age of the fibroblast donor cell on the gene expression profiles was also investigated. Aberrant expressions of DNMT1 and PCAF were found in some studied tissues, but the expression of MeCP2 and EED had similar levels to those of the normal controls. The expression of DNMT1 showed a higher level in heart, liver and brain of both cloned bovines. A higher ex- pression level of PCAF was seen in heart and liver of both cloned bovines, but a lower level was seen only in spleen of adult fibroblast (AF) cell-derived clones. Our results suggest that aberrant expression in gene that modified chromatins were found in cloned bovine tissues of neonatal death. Because DNMT1 and PCAF play an important role in DNA methylation and histone acetylation on nuclear chromatin respectively, and normal expression of DNMT1 and PCAF is needed for precious reprogramming of donor nuclear, the aberrant transcription patterns of DNMT1 andPCAF in these clones may contribute to the defects of organs reported in neonatal death of clones.展开更多
基金This work was supported by the Biology Program of Chinese National Foundation of"863"(Grant No.2001AA213091)by the Major Program of Natural Science Foundation of Beijing(Grant No.5030001).
文摘Cloning by somatic nuclear transfer is an inefficient process in which many of the cloned ani- mals died shortly after birth and displayed organ ab- normalities. In an effort to determine the possible genetic causes of neonatal death and organ abnor- malities, we have examined expression patterns of four genes that modified chromatin (DNMT1, PCAF,MeCP2 and EED) in six organs (heart, liver, spleen, lung, kidney and brain) of both neonatal death cloned bovines (n=9) and normal control calves produced by artificial insemination (AI) using real-time quantitative RT-PCR. The effect of the age of the fibroblast donor cell on the gene expression profiles was also investigated. Aberrant expressions of DNMT1 and PCAF were found in some studied tissues, but the expression of MeCP2 and EED had similar levels to those of the normal controls. The expression of DNMT1 showed a higher level in heart, liver and brain of both cloned bovines. A higher ex- pression level of PCAF was seen in heart and liver of both cloned bovines, but a lower level was seen only in spleen of adult fibroblast (AF) cell-derived clones. Our results suggest that aberrant expression in gene that modified chromatins were found in cloned bovine tissues of neonatal death. Because DNMT1 and PCAF play an important role in DNA methylation and histone acetylation on nuclear chromatin respectively, and normal expression of DNMT1 and PCAF is needed for precious reprogramming of donor nuclear, the aberrant transcription patterns of DNMT1 andPCAF in these clones may contribute to the defects of organs reported in neonatal death of clones.
