title: Promoter methylation and histone modifications affect the expression of the exogenous DsRed gene in transgenic goats.
abstract: Transgene silencing, which is common in transgenic plants and animals, limits the generation and application of genetically modified organisms, and is associated with the exogenous gene copy number, the methylation status of its promoters, and histone modification abnormalities. Here, we analyzed the expression of the exogenous gene DsRed and the methylation status of its cytomegalovirus (CMV) promoter in six healthy transgenic cashmere goats and transgenic nuclear donor cells. The CMV promoter exhibited high methylation levels (74.4-88.2%) in four of the goats, a moderate methylation level (58.7%) in one, and a low methylation level (21.2%) in one, while the methylation level of the transgenic nuclear donor cells was comparatively low (14.3%). DsRed expression was negatively correlated with promoter methylation status. Transgenic cashmere goats carried one to three copies of the CMV promoter fragment and one to six copies of the DsRed fragment, but copy number showed no obvious correlation with DsRed expression. After treatment with the methylation inhibitor 5-azacytidine, DsRed expression in transgenic goat cells significantly increased and CMV promoter methylation significantly decreased; this indicated an inverse correlation between promoter methylation status and DsRed expression. After treatment with the histone deacetylase inhibitor trichostatin A, DsRed expression increased, indicating that an abnormal histone modification in transgenic goats is also involved in exogenous gene silencing. These findings indicate the potential of trichostatin A and 5-azacytidine to rescue the biological activity of silenced exogenous transgenes in adult-derived transgenic cells under culture conditions.
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: M T
authors.initials: MT
authors.lastname: Nuo
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: W L
authors.initials: WL
authors.lastname: Yang
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: X Y
authors.initials: XY
authors.lastname: Gao
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: N
authors.initials: N
authors.lastname: He
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: H
authors.initials: H
authors.lastname: Liang
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China.
authors.forename: M
authors.initials: M
authors.lastname: Cang
authors.affiliation: Key Laboratory of Mammalian Reproductive Biology and Biotechnology of the Ministry of Education, Inner Mongolia University, Hohhot, Inner Mongolia, China nmliudongjun@sina.com.
authors.forename: D J
authors.initials: DJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001374:Azacitidine / Q000494:pharmacology*; D003587:Cytomegalovirus / Q000235:genetics; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D005260:Female; D018628:Gene Dosage; D015870:Gene Expression; D020868:Gene Silencing / Q000187:drug effects; D006041:Goats / Q000235:genetics*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D006877:Hydroxamic Acids / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D008297:Male; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D019076:Transgenes
chemical_list: D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D008164:Luminescent Proteins; C413663:fluorescent protein 583; C012589:trichostatin A; D004248:DNA (Cytosine-5-)-Methyltransferases; D006655:Histone Deacetylases; D001374:Azacitidine