The Caenorhabditis elegans gene unc-89, required fpr muscle M-line assembly, encodes a giant modular protein composed of Ig and signal transduction domains.
The Caenorhabditis elegans gene unc-89, required fpr muscle M-line assembly, encodes a giant modular protein composed of Ig and signal transduction domains.
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DOI：
10.1083/jcb.132.5.835
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发表时间：
1996-03
期刊：
影响因子：
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通讯作者：
Borodovsky M
中科院分区：
文献类型：
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作者：
Benian GM;Tinley TL;Tang X;Borodovsky M
秀丽隐杆线虫基因unc-89的突变导致线虫具有紊乱的肌肉结构，其中粗丝没有组织成A带，并且没有M线。从C. elegans测序计划中，我们已经克隆并测序了unc-89基因。发现unc-89等位基因st 515含有84-bp缺失和10-bp重复，导致在预测的unc-89编码序列内的框内终止密码子。对unc-89的完整编码序列的分析预测了一种新的6，632个氨基酸的多肽，其由涉及蛋白质-蛋白质相互作用的序列基序组成。cDNA-89起始于67个独特序列的残基，SH 3、dbl/CDC 24和PH结构域，7个免疫球蛋白（IG）结构域，一个推定的含KSP的多磷酸化结构域，并以46个IG结构域结束。针对unc-89编码序列的一部分产生的多克隆抗血清与来自野生型的抽搐大小的多肽发生反应，但与来自st 515和琥珀等位基因e2338的截短多肽发生反应。通过免疫荧光显微镜观察，该抗血清定位于A带的中间，与作为M线的结构组分的α-89一致。先前的研究表明，肌丝晶格组装开始于位于基底膜和肌细胞膜中的位置线索。我们提出，细胞内蛋白质的m-89响应这些信号，本地化，然后参与组装的M线。
Mutations in the Caenorhabditis elegans gene unc-89 result in nematodes having disorganized muscle structure in which thick filaments are not organized into A-bands, and there are no M-lines. Beginning with a partial cDNA from the C. elegans sequencing project, we have cloned and sequenced the unc-89 gene. An unc-89 allele, st515, was found to contain an 84-bp deletion and a 10-bp duplication, resulting in an in- frame stop codon within predicted unc-89 coding sequence. Analysis of the complete coding sequence for unc-89 predicts a novel 6,632 amino acid polypeptide consisting of sequence motifs which have been implicated in protein-protein interactions. UNC-89 begins with 67 residues of unique sequences, SH3, dbl/CDC24, and PH domains, 7 immunoglobulins (Ig) domains, a putative KSP-containing multiphosphorylation domain, and ends with 46 Ig domains. A polyclonal antiserum raised to a portion of unc-89 encoded sequence reacts to a twitchin-sized polypeptide from wild type, but truncated polypeptides from st515 and from the amber allele e2338. By immunofluorescent microscopy, this antiserum localizes to the middle of A-bands, consistent with UNC-89 being a structural component of the M-line. Previous studies indicate that myofilament lattice assembly begins with positional cues laid down in the basement membrane and muscle cell membrane. We propose that the intracellular protein UNC-89 responds to these signals, localizes, and then participates in assembling an M-line.