ANALYSIS OF THE PARAMYOSIN MINIPARAMYOSIN GENE - MINIPARAMYOSIN IS AN INDEPENDENTLY TRANSCRIBED, DISTINCT PARAMYOSIN ISOFORM, WIDELY DISTRIBUTED IN INVERTEBRATES
ANALYSIS OF THE PARAMYOSIN MINIPARAMYOSIN GENE - MINIPARAMYOSIN IS AN INDEPENDENTLY TRANSCRIBED, DISTINCT PARAMYOSIN ISOFORM, WIDELY DISTRIBUTED IN INVERTEBRATES
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DOI：
10.1074/jbc.270.9.4375
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发表时间：
1995-03-03
影响因子：
4.8
通讯作者：
CERVERA, M
中科院分区：
文献类型：
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作者：
MAROTO, M;ARREDONDO, JJ;CERVERA, M
微型副肌球蛋白是一种独特的黑腹果蝇副肌球蛋白亚型，大小为 60 kDa，此处显示其由与副肌球蛋白相同的基因编码。该基因位于 66D14，跨度超过 12.8 KB，并被组织成 10 个外显子，其中 9 个外显子编码副肌球蛋白转录物，位于外显子 7 和 8 之间的外显子编码微型副肌球蛋白的 5' 末端，并且这两个蛋白质共享该基因的最后两个外显子。这些转录物的 5' 末端的映射表明副肌球蛋白和微型副肌球蛋白 mRNA 来自两个重叠的转录单位；微型副肌球蛋白转录起始位点位于副肌球蛋白内含子内，位于用于副肌球蛋白转录的内含子下游 8 kb。两个不同启动子的存在及其序列的保守和非保守特征表明这两种肌肉蛋白的调节非常复杂。事实上，虽然副肌球蛋白与大多数其他果蝇肌肉蛋白一样在两个不同的发育阶段表达，但微型副肌球蛋白出现在发育后期，仅存在于成年肌肉组织中，在线虫秀丽隐杆线虫中，外显子 1B（微型副肌球蛋白的特定外显子）的缺失，作为额外的证据支持该特定生物体中缺乏微型副肌球蛋白。然而，它存在于所检查的大多数无脊椎动物物种中，包括不同的节肢动物、环节动物、软体动物和棘皮动物物种。
Miniparamyosin, a distinct Drosophila melanogaster paramyosin isoform of 60 kDa, is shown here to be encoded by the same gene as paramyosin. The gene, located at 66D14, spans over 12.8 kilobases (kb) and is organized into 10 exons, 9 of which code for the paramyosin transcripts, An exon, located between exons 7 and 8, codes for the 5'-end of the miniparamyosin, and the two proteins share the two last exons of the gene, Mapping of the 5'-ends of these transcripts indicates that the paramyosin and miniparamyosin mRNAs arise from two overlapping transcriptional units; the miniparamyosin transcription initiation site is located inside a paramyosin intron, 8 kb downstream of the one used for paramyosin transcription, The existence of two differ ent promoters and the conserved and nonconserved features of their sequences suggest a very complex regulation of these two muscle proteins, In fact, while paramyosin is expressed at two distinct stages of development as most other Drosophila muscle proteins, miniparamyosin appears late in development, being present only in the adult musculature, The absence of exon 1B, the specific exon of miniparamyosin, in the nematode Caenorhabditis elegans, as web as additional lines of evidence support the lack of miniparamyosin in this particular organism, However, it is present in most invertebrate species examined, including different arthropod, annelid, mollusc, and echinoderm species.