Moerman D G, Benian G M, Barstead R J, Schriefer L A, Waterston R H
Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110.
Genes Dev. 1988 Jan;2(1):93-105. doi: 10.1101/gad.2.1.93.
The unc-22 gene is one of a set of genes identified using classical genetics that affect muscle structure and function in the free-living nematode Caenorhabditis elegans. Since cloning the unc-22 gene by transposon tagging, we have used conventional techniques combined with a set of Tc1 transposon insertion alleles to characterize the gene and its products. The gene extends over more than 20 kb of genomic sequence and produces a transcript of approximately 14 kb. A polyclonal antibody raised against an Escherichia coli beta-galactosidase-unc-22 fusion protein recognizes a polypeptide in nematode extracts that is between 500,000 and 600,000 daltons and labels the muscle A-band in indirect immunofluorescent microscopy. The Tc1-induced alleles have been used at every stage to verify these conclusions. The Tc1 insertions are spread over much of the region that contributes to the mature transcript; in most alleles, Tc1 sequences are incorporated into a composite unc-22-Tc1 transcript. The large protein is either absent or severely reduced in amounts in the mutants. In one case, a truncated polypeptide was also identified. The location of the protein in the A-band, along with earlier genetic data, suggests that the unc-22 product may interact with myosin to regulate its function.
unc-22基因是利用经典遗传学鉴定出的一组影响自由生活线虫秀丽隐杆线虫肌肉结构和功能的基因之一。自通过转座子标签克隆unc-22基因以来，我们使用传统技术结合一组Tc1转座子插入等位基因来表征该基因及其产物。该基因跨越超过20kb的基因组序列，产生约14kb的转录本。针对大肠杆菌β-半乳糖苷酶-unc-22融合蛋白产生的多克隆抗体识别线虫提取物中的一种分子量在500,000至600,000道尔顿之间的多肽，并在间接免疫荧光显微镜下标记肌肉A带。在每个阶段都使用Tc1诱导的等位基因来验证这些结论。Tc1插入分布在对成熟转录本有贡献的大部分区域；在大多数等位基因中，Tc1序列被整合到复合unc-22-Tc1转录本中。在突变体中，大蛋白要么不存在，要么数量严重减少。在一个案例中，还鉴定出了一种截短的多肽。该蛋白在A带中的位置，连同早期的遗传数据，表明unc-22产物可能与肌球蛋白相互作用以调节其功能。
