Molecular analysis of the endosymbionts of tsetse flies: 16S rDNA locus and over-expression of a chaperonin
Molecular analysis of the endosymbionts of tsetse flies: 16S rDNA locus and over-expression of a chaperonin
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DOI：
10.1111/j.1365-2583.1995.tb00004.x
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发表时间：
1995-01-01
影响因子：
2.6
通讯作者：
Aksoy, S.
中科院分区：
文献类型：
--
作者：
Aksoy, S.
基于16 S rDNA序列比较，采采蝇（双翅目：舌蝇科）的细胞内菌体相关的内共生体（P-内共生体）形成一个独特的谱系内的γ-3亚类的变形菌，有关的自由生活的细菌大肠杆菌，中肠S-内共生体的各种昆虫，包括采采蝇，和P-内共生体谱系的蚜虫，Buchnera aphidicola。细胞内微生物中几个位点的基因组织和表达揭示了与自由生活的细菌的差异。本研究分析了采采蝇内共生菌的两个特征：rDNA操纵子的拷贝数和基因组织以及这些微生物合成的丰富蛋白质的性质。结果表明，Glossina morsitans morsitans S-内共生体有多个（7个）rDNA操纵子编码16 S（rrs），其次是23 S（rrl）基因序列，而采采蝇P-内共生体有一个单一的，类似的组织rDNA操纵子。在体外的采采蝇菌丝体中，P-内共生菌合成大小为60 kDa的主要蛋白质（p60），通过Western印迹分析，其显示与B的丰富的63 kDa（p63）蛋白质的免疫交叉反应性。蚜虫。p63（也称为共生蛋白）已被表征为分子伴侣，其结构和功能类似于大肠杆菌的groEL蛋白。杆菌在体外条件下，采采蝇S-内共生体合成高水平的类似大小的蛋白质，其与p63伴侣蛋白交叉反应。针对采采蝇p60蛋白的抗血清也识别B的p63蛋白。蚜虫，这表明丰富的采采蝇内共生体蛋白是伴侣蛋白。
Based on 16S rDNA sequence comparison, intracellular mycetome-associated endosymbionts (P-endosymbionts) of tsetse flies (Diptera: Glossinidae) form a distinct lineage within the gamma-3 subdivision of proteobacteria, related to the free living bacterium Escherichia coli, midgut S-endosymbionts of various insects including tsetse flies, and to the P-endosymbiont lineage of aphids, Buchnera aphidicola. Gene organization and expression of several loci in intracellular microorganisms have revealed differences from free-living bacteria. This study analyses two of these characteristics in tsetse endosymbionts; the copy number and gene organization of rDNA operons and the nature of the abundant protein(s) synthesized by these microorganisms. Results indicate that Glossina morsitans morsitans S-endosymbionts have multiple (seven) rDNA operons coding for 16S (rrs) followed by 23S (rrl) gene sequences, whereas tsetse P-endosymbionts have a single, similarly organized rDNA operon. In tsetse mycetocytes in vitro, P-endosymbionts synthesize a predominant protein of 60 kDa in size (p60) which by Western blot analysis shows immunological cross-reactivity with the abundant 63 kDa (p63) protein of B. aphidicola. p63 (also referred to as symbionin) has been characterized as a molecular chaperone, structurally and functionally similar to the groEL protein of E. coli. Under in vitro conditions, tsetse S-endosymbionts synthesize high levels of a similarly-sized protein that cross-reacts with p63 chaperonin. Antisera against the tsetse p60 protein also recognizes p63 protein of B. aphidicola, suggesting that the abundant tsetse endosymbiont protein is a chaperonin.