Kapoor S, Wakasugi T, Deno H, Sugiura M
Center for Gene Research, Nagoya University, Japan.
Curr Genet. 1994 Sep;26(3):263-8. doi: 10.1007/BF00309558.
The atpB and atpE genes encode beta and epsilon subunits, respectively, of chloroplast ATP synthase and are co-transcribed in the plant species so far studied. In tobacco, an atpB gene-specific probe hybridizes to 2.7- and 2.3-kb transcripts. In addition to these, a probe from the atpE coding region hybridizes also to a 1.0-kb transcript. The 5' end of the atpE-specific transcript has been mapped 430/431 nt upstream of the atpE translation initiation site, within the coding region of the atpB gene. In-vitro capping revealed that this transcript results from a primary transcriptional event and is also characterized by -10 and -35 canonical sequences in the 5' region. It has been found to share a common 3' end with the bi-cistronic transcripts that has been mapped within the coding region of the divergently transcribed trnM gene, approximately 236 nt downstream from the atpE termination codon. Interestingly, this transcript accumulates only in leaves and not in proplastid-containing cultured (BY-2) cells, indicating that, unless it is preferentially degraded in BY-2 cells, its expression might be transcriptionally controlled.
atpB和atpE基因分别编码叶绿体ATP合酶的β亚基和ε亚基，并且在目前已研究的植物物种中是共同转录的。在烟草中，一个atpB基因特异性探针与2.7 kb和2.3 kb的转录本杂交。除此之外，一个来自atpE编码区的探针也与一个1.0 kb的转录本杂交。atpE特异性转录本的5′端已定位在atpE翻译起始位点上游430/431 nt处，位于atpB基因的编码区内。体外加帽显示该转录本源自一次初级转录事件，并且在其5′区域还具有典型的-10和-35序列特征。已发现它与双顺反子转录本具有共同的3′端，该双顺反子转录本已定位在反向转录的trnM基因的编码区内，位于atpE终止密码子下游约236 nt处。有趣的是，这种转录本仅在叶片中积累，而在含有前质体的培养（BY-2）细胞中不积累，这表明，除非它在BY-2细胞中被优先降解，否则其表达可能受转录调控。
