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Developmental‐stage‐specific plasmid supercoiling in Chlamydia trachomatis
Author(s) -
Solbrig M. V.,
Wong M. L.,
Stephens R. S.
Publication year - 1990
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1990.tb02064.x
Subject(s) - dna supercoil , biology , plasmid , microbiology and biotechnology , chlamydia trachomatis , dna , gel electrophoresis , plasmid preparation , genetics , pbr322 , dna replication , virology
Summary Chlamydia trachomatis elementary body (EB) and reticulate body (RB) developmental stages have polymorphic plasmid DNA. Several plasmid forms separated by gel electrophoresis were identified as topoisomers by treatment with topoisomerase I. Among these topoisomers was one form unique to EBs and one form unique to RBs. The unique EB plasmid topoisomer was characterized as highly supercoiled, on the basis of band migrations by gel electrophoresis and its appearance by electron microscopy. The unusual physical state of this topoisomer was probably mediated, in part, by DNA‐specific structural proteins. The unique RB plasmid topoisomer was a supercoiled form of lower superhelical density than the other identified topoisomers. Developmental‐stage‐specific differences in superhelical density of plasmid DNA suggest cause‐and effect relationships between DNA topology and metabolic activity in RBs and metabolic quiescence in EBs.