Genetic analysis of ryanodine receptor function in Caenorhabditis elegans based on unc-68 revertants
Genetic analysis of ryanodine receptor function in Caenorhabditis elegans based on unc-68 revertants
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DOI：
10.1007/s00438-003-0892-5
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发表时间：
2003-08-01
影响因子：
3.1
通讯作者：
Kagawa, H
中科院分区：
文献类型：
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作者：
Adachi, R;Kagawa, H
秀丽隐杆线虫ryanodine受体由unc-68基因编码，在肌肉收缩过程中作为Ca 2+诱导的Ca 2+释放通道发挥作用。为了研究抑制钙释放的因素并鉴定与兰尼碱受体相互作用的分子，我们从两个unc-68突变体中分离了回复突变体。从无效等位基因unc-68（e540）获得的回复突变体中，有三个显示正常的运动性，有基因内突变，导致未能剪接出内含子21。另外两个，kh 53和kh 55，在四个RyR结构域的第三个中有氨基酸插入。这些回复突变体的窝卵数和产卵率仍然异常。这表明第三个RyR结构域可能是产卵和胚胎发生所必需的，尽管我们不能确定分子机制。从错义突变体unc-68（kh 30）中回收的5个氯胺酮敏感回复突变体显示，相对于unc-68（kh 30）动物，对咖啡因、兰尼定、左旋咪唑和哇巴因的反应发生了改变。这些可能携带第二位点抑制突变，这可能定义了调节体壁肌肉中Ca 2+浓度的蛋白质的基因。其中一个突变体kh 52显示出较低的运动性和对药物的较高敏感性，并且该突变被定位于X染色体。这些观察结果为研究ryanodine受体在胚胎发生和钙介导的肌肉收缩调节中的功能提供了基础。优雅这是第一个研究表明，保守的RyR结构域的受体作用于产卵和胚胎发生。
The Caenorhabditis elegans ryanodine receptor is encoded by the unc-68 gene, and functions as a Ca2+-induced Ca2+ release channel during muscle contraction. To investigate the factors that suppress calcium release and identify molecules that interact with the ryanodine receptor, we isolated revertants from two unc-68 mutants. Three of the revertants obtained from the null allele unc-68(e540), which displayed normal motility, had intragenic mutations that resulted in failure to splice out intron 21. The other two, kh53 and kh55, had amino acid insertions in the third of the four RyR domains. The brood size and the egg laying rate remain abnormal in these revertants. This suggests the third RyR domain may be required for egg laying and embryogenesis, although we can not determine a molecular mechanism. Five ketamine sensitive revertants recovered from the missense mutant unc-68(kh30) showed altered responses to caffeine, ryanodine, levamisole and ouabain relative to those of the unc-68(kh30) animals. These may carry second-site suppressor mutations, which may define genes for proteins that regulate the Ca2+ concentration in body-wall muscle. One of these mutants, kh52 , shows lower motility and higher sensitivity to drugs, and this mutation was mapped to chromosome X. These observations provide a basis for the study of ryanodine receptor functions in embryogenesis and in calcium-mediated regulation of muscle contraction in C. elegans. This is the first study to show that the conserved RyR domain of the receptor acts in egg laying and embryogenesis.