کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2187364 1096113 2008 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Genetic Dissection of the Consensus Sequence for the Class 2 and Class 3 Flagellar Promoters
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Genetic Dissection of the Consensus Sequence for the Class 2 and Class 3 Flagellar Promoters
چکیده انگلیسی

Computational searches for DNA binding sites often utilize consensus sequences. These search models make assumptions that the frequency of a base pair in an alignment relates to the base pair's importance in binding and presume that base pairs contribute independently to the overall interaction with the DNA-binding protein. These two assumptions have generally been found to be accurate for DNA binding sites. However, these assumptions are often not satisfied for promoters, which are involved in additional steps in transcription initiation after RNA polymerase has bound to the DNA. To test these assumptions for the flagellar regulatory hierarchy, class 2 and class 3 flagellar promoters were randomly mutagenized in Salmonella. Important positions were then saturated for mutagenesis and compared to scores calculated from the consensus sequence. Double mutants were constructed to determine how mutations combined for each promoter type. Mutations in the binding site for FlhD4C2, the activator of class 2 promoters, better satisfied the assumptions for the binding model than did mutations in the class 3 promoter, which is recognized by the σ28 transcription factor. These in vivo results indicate that the activator sites within flagellar promoters can be modeled using simple assumptions, but that the DNA sequences recognized by the flagellar sigma factor require more complex models.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 379, Issue 5, 20 June 2008, Pages 936–952
نویسندگان
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