Identification and characterization of a regulatory sequence recognized by Mycobacterium tuberculosis persistence regulator MprA.
Establishment and maintenance of persistent, latent infection by Mycobacterium tuberculosis are dependent on expression of the mprA-mprB regulatory system. Previously, MprA and MprB were shown to participate in phosphotransfer reactions characteristic of two-component signaling systems. To begin identifying downstream effector genes regulated by mprA-mprB during persistent stages of infection, a search for the regulatory sequence(s) recognized by response regulator MprA was carried out. Here, evidence is presented demonstrating that MprA recognizes a 19-bp sequence comprising two loosely conserved 8-bp direct repeat subunits separated by 3 nucleotides. This motif, termed the MprA box, is found upstream of the mprA coding sequence and that of downstream gene pepD (Rv0983). Protein phosphorylation was not required for binding to this DNA sequence by MprA in vitro; however, phosphorylation enhanced DNA binding by MprA and was required for the regulation of mprA and pepD by MprA in vivo. Binding of MprA to the MprA box was dependent on conserved nucleotides contained within repeat subunits and on the spacer length separating these repeats. In addition, recognition of this sequence proceeded via tandem binding of two monomers of MprA. Identification of the genetic determinants regulated by MprA will ultimately enhance our understanding of the mechanisms utilized by M. tuberculosis to undergo latency.
He
Hongjun
H
Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Rd., P.O. Box 26509, Milwaukee, WI 53226, USA.
Zahrt
Thomas C
TC
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D010766:Phosphorylation; D020449:Repetitive Sequences, Amino Acid
D001426:Bacterial Proteins; C480224:MprA protein, Mycobacterium tuberculosis; D004247:DNA