title: The ovalbumin gene family: hormonal control of X and Y gene transcription and mRNA accumulation.
abstract: The ovalbumin gene family is composed of three genes, X, Y and ovalbumin, which are expressed in laying hen oviduct. We have analyzed the in vivo transcription products of X and Y genes and the effect of steroid hormones on their synthesis and accumulation. As in the case of ovalbumin, the complete gene transcripts and processing intermediates are present in the poly(A)+ RNA fraction. The mature RNAs are found in polysomes and are translated into proteins. The expression of X and Y genes is controlled by steroid hormones: X and Y RNAs are not detectable in oviducts from chicks withdrawn from estrogen stimulation, whereas in chicks stimulated with estrogen for 7 days, X RNA represents 0.3% and Y RNA 0.8% of ovalbumin mRNA. In laying hen, however, the levels of X and Y RNAs are about 2% of ovalbumin mRNA. After stimulation with other steroid hormones, alone or in combination, the level of X and Y RNA does not achieve that detected in laying hen. Progesterone has a much weaker effect on X RNA accumulation than on that of Y and ovalbumin mRNAs. Studies with isolated nuclei show that X and Y gene expression is regulated by hormones at the level of transcription. However, the differences observed between the transcription rates and the accumulation of X and Y mRNAs suggest that the expression of X and Y genes could also be controlled at the levels of RNA processing and/or mRNA stability.
mesh_terms: D000818:Animals; D002645:Chickens; D003907:Dexamethasone / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation; D005796:Genes; D006728:Hormones / Q000494:pharmacology*; D010047:Ovalbumin / Q000235:genetics*; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D013739:Testosterone / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D006728:Hormones; D012333:RNA, Messenger; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D003907:Dexamethasone; D010047:Ovalbumin