The regulatory action of the myxobacterial CarD/CarG complex: a bacterial enhanceosome?
A global regulatory complex made up of two unconventional transcriptional factors, CarD and CarG, is implicated in the control of various processes in Myxococcus xanthus, a Gram-negative bacterium that serves as a prokaryotic model system for multicellular development and the response to blue light. CarD has a unique two-domain architecture composed of: (1) a C-terminal DNA-binding domain that resembles eukaryotic high mobility group A (HMGA) proteins, which are relatively abundant, nonhistone components of chromatin that remodel DNA and prime it for the assembly of multiprotein-DNA complexes essential for various DNA transactions, and (2) an N-terminal domain involved in interactions with CarG and RNA polymerase, which is also the founding member of the large CarD_TRCF family of bacterial proteins. CarG, which does not bind DNA directly, has a zinc-binding motif of the type found in the archaemetzincin class of metalloproteases that, in CarG, appears to play a purely structural role. This review aims to provide an overview of the known molecular details and insights emerging from the study of the singular CarD-CarG prokaryotic regulatory complex and its parallels with enhanceosomes, the higher order, nucleoprotein transcription complexes in eukaryotes.
Elías-Arnanz
Montserrat
M
Departamento de Genética y Microbiología, Area de Genética (Unidad Asociada al IQFR-CSIC), Facultad de Biología, Universidad de Murcia, Murcia, Spain.
Padmanabhan
S
S
Murillo
Francisco J
FJ
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D024003:HMGA Proteins / Q000235:genetics* / Q000378:metabolism; D016941:Myxococcus xanthus / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D050880:p300-CBP Transcription Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; C100589:CarD protein, Myxococcus xanthus; D024003:HMGA Proteins; D015534:Trans-Activators; D050880:p300-CBP Transcription Factors