Hastings M L, Milcarek C, Martincic K, Peterson M L, Munroe S H
Department of Biology, Marquette University, Milwaukee, WI 53233, USA.
Nucleic Acids Res. 1997 Nov 1;25(21):4296-300. doi: 10.1093/nar/25.21.4296.
The erbAalpha gene encodes two alpha-thyroid hormone receptor isoforms, TRalpha1 and TRalpha2, which arise from alternatively processed mRNAs, erbAalpha1 (alpha1) and erb alpha2 (alpha2). The splicing and alternative polyadenylation patterns of these mRNAs resemble that of mRNAs encoding different forms of immunoglobulin heavy chains, which are regulated at the level of alternative processing during B cell differentiation. This study examines the levels of erbAalpha mRNA in eight B cell lines representing four stages of differentiation in order to determine whether regulation of the alternatively processed alpha1 and alpha2 mRNAs parallels the processing of immunoglobulin heavy chain mRNAs. Results show that the pattern of alpha1 and alpha2 mRNA expression is clearly different from that observed for immunoglobulin heavy chain mRNAs. B cell lines display characteristic ratios of alpha1/alpha2 mRNA at distinct stages of differentiation. Furthermore, expression of an overlapping gene, Rev-ErbAalpha (RevErb), was found to correlate strongly with an increase in the ratio of alpha1/alpha2 mRNA. These results suggest that alternative processing of erbAalpha mRNAs is regulated by a mechanism which is distinct from that regulating immunoglobulin mRNA. The correlation between RevErb and erbAalpha mRNA is consistent with negative regulation of alpha2 via antisense interactions with the complementary RevErb mRNA.
erbAalpha基因编码两种α-甲状腺激素受体亚型，即TRalpha1和TRalpha2，它们由经过不同加工的mRNA，即erbAalpha1（α1）和erb alpha2（α2）产生。这些mRNA的剪接和可变聚腺苷酸化模式类似于编码不同形式免疫球蛋白重链的mRNA的模式，后者在B细胞分化过程中在可变加工水平受到调控。本研究检测了代表分化四个阶段的八个B细胞系中erbAalpha mRNA的水平，以确定可变加工的α1和α2 mRNA的调控是否与免疫球蛋白重链mRNA的加工平行。结果表明，α1和α2 mRNA的表达模式与免疫球蛋白重链mRNA的明显不同。B细胞系在不同分化阶段显示出α1/α2 mRNA的特征性比例。此外，发现一个重叠基因Rev-ErbAalpha（RevErb）的表达与α1/α2 mRNA比例的增加密切相关。这些结果表明，erbAalpha mRNA的可变加工受一种不同于调控免疫球蛋白mRNA的机制调控。RevErb与erbAalpha mRNA之间的相关性与通过与互补的RevErb mRNA进行反义相互作用对α2进行负调控一致。
