Identification of an activity in B-cell extracts that selectively impairs the formation of an immunoglobulin mu s poly(A) site processing complex.
Identification of an activity in B-cell extracts that selectively impairs the formation of an immunoglobulin mu s poly(A) site processing complex.
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鉴定 B 细胞提取物中选择性损害免疫球蛋白 mu s poly(A) 位点加工复合物形成的活性。
DOI：
10.1128/mcb.15.4.1901
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发表时间：
1995
影响因子：
5.3
通讯作者：
Nevins,JR
中科院分区：
文献类型：
--
作者：
Yan,DH;Weiss,EA;Nevins,JR
免疫球蛋白m重链转录单位在B细胞发育过程中差异表达，产生编码分泌型（ms）和膜结合型（mm）重链多肽的mRNA。尽管ms mRNA和mm mRNA在B细胞中以大致相等的丰度产生，但ms poly（A）位点利用的增加有助于ms mRNA作为浆细胞中的主要形式产生。先前的实验已经证明了在poly（A）位点上形成稳定复合物与poly（A）位点的相对功能之间的相关性。因此，我们研究了确定这些因子与免疫球蛋白poly（A）位点相互作用的参数。通过使用HeLa细胞活性对涉及两个免疫球蛋白poly（A）位点的复合物形成的测定揭示了稳定复合物的形成，ms位点和mm位点之间没有明显差异。相反，当使用B细胞提取物时，ms特异性复合物明显不稳定。B细胞提取物的分级分离揭示了特异性地使ms多聚腺苷酸化复合物不稳定的活性，这表明该poly（A）位点的功能可能受正作用因子和负作用因子的调节。
The immunoglobulin m heavy-chain transcription unit is differentially expressed during B-cell development, producing mRNAs that encode secreted (ms) and membrane-bound (mm) forms of the heavy-chain polypeptide. Whereas the ms mRNA and the mm mRNA are produced in approximately equal abundance in B cells, an increase in the utilization of the ms poly(A) site contributes to the production of the ms mRNA as the predominant form in a plasma cell. Previous experiments have demonstrated a correlation between the formation of a stable complex on a poly(A) site and the relative function of the poly(A) site. We have thus investigated the parameters determining the interaction of these factors with the immunoglobulin poly(A) sites. Assays of complex formation involving the two immunoglobulin poly(A) sites by using HeLa cell activities revealed the formation of stable complexes with no apparent difference between the ms site and the mm site. In contrast, the ms-specific complex was markedly less stable when a B-cell extract was used. Fractionation of B-cell extracts has revealed an activity that specifically destabilizes the ms polyadenylation complex, suggesting that the function of this poly(A) site may be regulated by both positive- and negative-acting factors.