title: Right-handed DNA supercoiling by an octameric form of histone-like protein HU: modulation of cellular transcription.
abstract: In bacteria, the contribution of global nucleoid organization in determining cellular transcription programs is unclear. Using a mutant form of the most abundant nucleoid-associated protein HU, HUalpha(E38K,V42L), we previously showed that nucleoid remodeling by the mutant protein re-organizes the global transcription pattern. Here, we demonstrate that, unlike the dimeric wild-type HU, HUalpha(E38K,V42L) is an octamer and wraps DNA around its surface. The formation of wrapped nucleoprotein complexes by HUalpha(E38K,V42L) leads to a high degree of DNA condensation. The DNA wrapping is right-handed, which restrains positive supercoils. In vivo, HUalpha(E38K,V42L) shows altered association and distribution patterns with the genetic loci whose transcription are differentially affected in the mutant strain.
authors.affiliation: Laboratory of Molecular Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Sudeshna
authors.initials: S
authors.lastname: Kar
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Choi
authors.forename: Fusheng
authors.initials: F
authors.lastname: Guo
authors.forename: Emilios K
authors.initials: EK
authors.lastname: Dimitriadis
authors.forename: Svetlana L
authors.initials: SL
authors.lastname: Kotova
authors.forename: Sankar
authors.initials: S
authors.lastname: Adhya
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D002843:Chromatin / Q000737:chemistry / Q000235:genetics; D004278:DNA, Superhelical / Q000737:chemistry* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D005819:Genetic Markers; D018698:Glutamic Acid / Q000235:genetics; D006657:Histones / Q000737:chemistry* / Q000235:genetics; D007930:Leucine / Q000235:genetics; D008239:Lysine / Q000235:genetics; D018625:Microscopy, Atomic Force; D009154:Mutation; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D014633:Valine / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D002843:Chromatin; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D005819:Genetic Markers; D006657:Histones; D020033:Protein Isoforms; D014157:Transcription Factors; C116822:hns protein, E coli; C490937:hupA protein, E coli; D018698:Glutamic Acid; D007930:Leucine; D014633:Valine; D008239:Lysine