Disease relevance of mukB

• mukF, mukE and mukB genes are essential for the process of chromosome partitioning in Escherichia coli [1].
• Mutants suppressing novobiocin hypersensitivity of a mukB null mutation [2].

High impact information on mukB

• mukB mutants of Escherichia coli are defective in the correct partitioning of replicated chromosomes [3].
• Based on the nucleotide sequence of the mukB gene, the MukB protein of 177 kDa was predicted to be a filamentous protein with globular domains at the ends, and also having DNA binding and nucleotide binding abilities [3].
• The most surprising result of this study was revealed upon further examination of FtsZ ring positioning in anucleate cells generated by the parC and mukB mutants: many of these cells, despite having no chromosome, possessed FtsZ rings at their midpoints [4].
• However, none of them could suppress both phenotypes in a mukB null mutation [5].
• We found that NO was mostly normal in cells with inactivated DNA gyrase or in mukB-null mutants lacking topA, although some suppression of NO was evident in the latter case [6].

Biological context of mukB

• When kicA disruptant cells bearing a temperature-sensitive replication plasmid carrying the kicA+ gene were grown at 30 degrees C and then transferred to 42 degrees C, the mutant cells gradually lost colony-forming ability, even in the presence of a mukB+ plasmid [7].
• These phenotypes are the same as those observed in the mukB null mutant [8].
• The nucleotide sequence was determined of the region upstream of the mukB gene of Escherichia coli [7].
• The E. coli MukB protein is required for proper chromosomal positioning, so that mukB mutants generate some cells without chromosomes (anucleate cells) at each cell division [9].
• Two mutant alleles of mukB, a gene essential for chromosome partition in Escherichia coli [10].

Associations of mukB with chemical compounds

• We found that in the mukB mutant, the process of sister chromosome segregation is strikingly hypersensitive to novobiocin; however, the effect of novobiocin on growth, which was measured by culture turbidity, is the same as that of the wild-type strain [2].
• These mutant mukB genes were each found to carry a single base-pair transition which leads to an amino acid substitution; a serine residue at position 33 was changed to phenylalanine in the case of mukB106, and an aspartic acid residue at position 1201 was changed to asparagine in the case of mukB33 [10].

Other interactions of mukB

• In null mutants for the mukF, mukE, and mukB genes, the synchronous initiation of chromosome replication was not affected [8].
• Combining the corresponding truncated ftsK gene with a mukB null mutation resulted in a synthetic lethal phenotype [11].
• A mukB null mutant is hypersensitive to the DNA gyrase inhibitor novobiocin [2].

References