Gorab E, Botella L M, Quinn J P, Amabis J M, Díez J L
Centro de Investigaciones Biológicas (CSIC), Velázquez 144, E-28006 Madrid, Spain.
Chromosoma. 1996 Sep;105(3):150-7. doi: 10.1007/BF02509496.
Antigens of Chironomus reactive with human sera containing anti-Ku antibodies and also with specific antibodies to each Ku subunit were characterized by immunoblot analysis. Three main antigen species were identified in nuclear-enriched extracts from salivary gland cells of Chironomus thummi, ranging in Mr from 55000 to 67000. The nuclear localization of Ku-related antigens in the dipteran Chironomus was studied by immunofluorescent labeling in polytene chromosomes of the salivary glands. Balbiani rings, loci highly active in transcription, were found to be strongly labeled by anti-Ku antibodies. Sugar-induced changes in the activity of the Balbiani ring genes were accompanied by the redistribution of Ku-related antigens as visualized by their absence in regressed Balbiani ring loci, and continued presence only in those that were transcriptionally active. A drastic change in the distribution of Ku-related antigens was also observed when C. thummi larvae underwent heat treatment as the immunofluorescent staining was restricted to previously described heat shock puffs. Anti-Ku sera reacted in addition with several chromosomal bands in which the presence of RNA polymerase II was also immunologically detected. The results show that Chironomus antigens reactive with anti-Ku antibodies are related to transcription in polytene chromosomes.
通过免疫印迹分析对与含抗Ku抗体的人血清以及与每个Ku亚基的特异性抗体发生反应的摇蚊抗原进行了表征。在嗜菌摇蚊唾液腺细胞富含核的提取物中鉴定出三种主要抗原种类，其分子量在55000至67000之间。通过对唾液腺多线染色体进行免疫荧光标记，研究了双翅目摇蚊中Ku相关抗原的核定位。发现转录高度活跃的位点巴尔比亚尼环被抗Ku抗体强烈标记。巴尔比亚尼环基因活性的糖诱导变化伴随着Ku相关抗原的重新分布，这通过在退化的巴尔比亚尼环位点中看不到它们以及仅在转录活跃的位点中持续存在而得以体现。当嗜菌摇蚊幼虫接受热处理时，也观察到Ku相关抗原分布的剧烈变化，因为免疫荧光染色仅限于先前描述的热休克胀泡。抗Ku血清还与几个染色体带发生反应，在这些带中也通过免疫检测到了RNA聚合酶II的存在。结果表明，与抗Ku抗体发生反应的摇蚊抗原与多线染色体中的转录有关。
