五个链霉菌线型质粒端粒的克隆和分析

Cloning and analysis of the telomeres of five Streptomyces linear plasmids

摘要:

摘要：本室从西藏采集的土壤样品中分离到了一批链霉菌，利用脉冲电泳确定了其中5株链霉菌含有较小的线型质粒。【目的】克隆、测序和分析5个线型质粒的端粒。【方法】采用改良的“在凝胶中进行DNA碱处理和限制性内切酶酶切”的方法来克隆线型质粒的端粒DNA。【结果】克隆和测序了5个线型质粒的端粒DNA。通过与链霉菌典型端粒进行比较，发现这5个新的线型质粒的端粒序列同样含有多个回文序列。但是有的端粒保守的回文序列I不一定能够“折返”与内部序列配对形成“超级发卡”结构，回文序列的“突出环”不一定都为3 nt。【结论】采用改良的方法克隆和鉴定了5个线型质粒新的端粒序列，这些新端粒的特征暗示：回文序列I的“折返”和3 nt的回文序列的“突出环”不是端粒复制必需的。

Abstract:

Abstract: Streptomyces strains were isolated from soil samples of Tibet, five small linear plasmids were detected by pulsed-field gel electrophoresis. [Objective] Cloning, sequencing and analysis of telomeres of these plasmids. [Methods] The telomeres were cloned by a modified procedure — “alkaline treatment and enzyme digestion in gels”. [Results] Telomeres of five linear plasmids were cloned and sequenced. Compared with the typical Streptomyces telomeres, the newly identified telomeres contained multiple palindromes, but some could not “fold-back” of their first conserved palindrome I with the internal palindromes to form a “super-hairpin”, and palindromes of some telomeres did not contain the 3-nt “loop”. [Conclusion] New telomere sequences were cloned by a modified procedure. Both folding-back of the telomere palindromes and 3-nt loop of palindromes varied among telomeres.