Genetic analysis of the chromosome segregation protein Spo0J of Bacillus subtilis: evidence for separate domains involved in DNA binding and interactions with Soj protein

Citation
S. Autret et al., Genetic analysis of the chromosome segregation protein Spo0J of Bacillus subtilis: evidence for separate domains involved in DNA binding and interactions with Soj protein, MOL MICROB, 41(3), 2001, pp. 743-755
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
MOLECULAR MICROBIOLOGY
ISSN journal
0950-382X → ACNP
Volume
41
Issue
3
Year of publication
2001
Pages
743 - 755
Database
ISI
SICI code
0950-382X(200108)41:3<743:GAOTCS>2.0.ZU;2-R
Abstract
Spo0J and Soj belong to the ParB/ParA family of proteins involved in chromo some and plasmid segregation in bacteria. In Bacillus subtilis, Spo0J prote in binds to several specific sites, parS, located on both sides of the orig in of DNA replication, oriC, and apparently self-associates to form large d iscrete foci visible by fluorescence microscopy. Soj protein forms large 'p atches' probably associated with the nucleoid, which can undergo dynamic, c o-operative jumping from nucleoid to nucleoid in the presence of Spo0J. Pat ches of Soj protein somehow help to bring about the condensation of Spo0J f oci. Soj is also a negative regulator of transcription. In the absence of S po0J, Soj is statically distributed on each of the nucleoids in the cell an d blocks the transcription of several sporulation genes. To analyse the fun ctional interaction between Spo0J and Soj further, we have constructed and studied a collection of spo0J mutants. Most of the mutants completely preve nt Spo0J from interacting with DNA. One mutation impairs the formation of c ompact Spo0J foci and simultaneously results in loss of Soi movement. We al so isolated one spo0J mutant, in which the frequency of Soj internucleoid o scillation is highly increased. Both mutations affecting the interaction wi th Soj lie in the N-terminal coding part of spo0J, whereas the substitution s affecting DNA binding lie in the mid- to C-termInaI coding region.