Structure, sequence and expression of the mouse Cx43 gene encoding connexin 43.
Structure, sequence and expression of the mouse Cx43 gene encoding connexin 43.
复制标题
编码连接蛋白 43 的小鼠 Cx43 基因的结构、序列和表达。
DOI：
10.1016/0378-1119(93)90419-4
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发表时间：
1993
期刊：
影响因子：
3.5
通讯作者：
Lo,CW
中科院分区：
文献类型：
--
作者：
Sullivan,R;Ruangvoravat,C;Joo,D;Morgan,J;Wang,BL;Wang,XK;Lo,CW
缝隙连接是调节细胞间离子和小分子扩散的膜通道，被认为在发育和生长调节中发挥作用。Cx43基因(编码缝隙连接蛋白43)是缝隙连接基因家族的成员之一，其转录产物在小鼠发育过程中以高度区域化的方式表达。我们从一个7.5天的小鼠胚胎c DNA文库中克隆并测序了Cx43的cDNAs。这些克隆编码43 kDa的连接蛋白。对从7.5天的小鼠胚胎不同区域提取的RNA的分析表明，Cx43转录本存在差异表达，在胚胎本身中检测到表达，但在包含外胎盘锥体的胚胎外3区域没有表达。利用其中一个新分离的小鼠Cx43基因探针，筛选小鼠基因组DNA文库，克隆了Cx43基因。限制性内切酶图谱和测序结果表明，Cx43含有两个外显子和一个10.5kb的内含子，位于5‘非翻译区。我们通过RNase保护和引物延伸分析定位了Cx43的转录起点(TSP)，结果表明，在7.5天的小鼠胚胎和成年组织中表达的转录产物都是由相同的TSP起始的。紧邻TSP上游的DNA序列包含一个推测的AP1结合位点和一个简并的TATA共识序列。对小鼠、大鼠、人和牛Cx43s的比较表明，3‘-UTRs具有出人意料的高度同源性。这包括四个AUUUA基序的保守，这是一个与即刻早期基因的转录不稳定性相关的序列。然而，进一步分析Cx43在NIH3T3和BALB/c 3T3细胞中的表达表明，Cx43的表达不受血清的诱导，这一点在即刻早期基因中已被发现。
Gap junctions, membrane channels that mediate the diffusion of ions and small molecules between cells, are hypothesized to play a role in development and growth regulation. TheCx43 gene (encoding connexin 43) is one member of the gap junction gene family whose transcripts are expressed in a highly regionalized manner during mouse development. We cloned and sequencedCx43 cDNAs from a 7.5-day mouse embryo cDNA library. These cDNA clones encode the authentic 43-kDa connexin. Analysis of RNA isolated from different regions of the 7.5-day mouse embryo revealed thatCx43 transcripts are differentially expressed, with expression detected in the embryo proper, but not in the extraembryonic 3 region containing the ectoplacental cone. Using one of the newly isolated mouseCx43 cDNA probes, we screened a mouse genomic DNA library and cloned theCx43gene. Restriction mapping and sequencing of the cloned genomic inserts revealed thatCx43 contains two exons and a 10.5-kb intron located in the 5' untranslated region (5'-UTR). We mapped theCx43 transcription start point (tsp) by RNase protection and primer extension analyses and showed that transcripts expressed in the 7.5-day mouse embryo and in adult tissues are initiated from the sametsp. The DNA sequence immediately upstream from the tsp contains a putative AP1-binding site and a degenerate TATA consensus sequence. A comparison of mouse, rat, human and bovineCx43s showed that the 3'-UTRhas an unexpectedly high degree of sequence homology. This includes conservation of four AUUUA motifs, a sequence associated with transcript instability in immediate early genes. However, further analysis ofCx43 expression in NIH 3T3 and BALB/c 3T3 cells showed thatCx43 expression is not subject to serum induction, as has been found for the immediate early genes.