This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cayuela, M. L. Articles by Murillo, F. J. Search for Related Content PubMed PubMed Citation Articles by Cayuela, M. L. Articles by Murillo, F. J.

The Stigmatella aurantiaca Homolog of Myxococcus xanthus High-Mobility-Group A-Type Transcription Factor CarD: Insights into the Functional Modules of CarD and Their Distribution in Bacteria

María L. Cayuela, Montserrat Elías-Arnanz, Marcos Peñalver-Mellado, S. Padmanabhan, and Francisco J. Murillo^*

Departamento de Genética y Microbiología, Universidad de Murcia, 30100 Murcia, Spain

Received 21 January 2003/ Accepted 25 March 2003

Transcriptional factor CarD is the only reported prokaryotic analog of eukaryotic high-mobility-group A (HMGA) proteins, in that it has contiguous acidic and AT hook DNA-binding segments and multifunctional roles in Myxococcus xanthus carotenogenesis and fruiting body formation. HMGA proteins are small, randomly structured, nonhistone, nuclear architectural factors that remodel DNA and chromatin structure. Here we report on a second AT hook protein, CarD_Sa, that is very similar to CarD and that occurs in the bacterium Stigmatella aurantiaca. CarD_Sa has a C-terminal HMGA-like domain with three AT hooks and a highly acidic adjacent region with one predicted casein kinase II (CKII) phosphorylation site, compared to the four AT hooks and five CKII sites in CarD. Both proteins have a nearly identical 180-residue N-terminal segment that is absent in HMGA proteins. In vitro, CarD_Sa exhibits the specific minor-groove binding to appropriately spaced AT-rich DNA that is characteristic of CarD or HMGA proteins, and it is also phosphorylated by CKII. In vivo, CarD_Sa or a variant without the single CKII phosphorylation site can replace CarD in M. xanthus carotenogenesis and fruiting body formation. These two cellular processes absolutely require that the highly conserved N-terminal domain be present. Thus, three AT hooks are sufficient, the N-terminal domain is essential, and phosphorylation in the acidic region by a CKII-type kinase can be dispensed with for CarD function in M. xanthus carotenogenesis and fruiting body development. Whereas a number of hypothetical proteins homologous to the N-terminal region occur in a diverse array of bacterial species, eukaryotic HMGA-type domains appear to be confined primarily to myxobacteria.

Present address: Department of Immunology and Oncology, Centro Nacional de Biotecnología-CSIC, E-28049 Madrid, Spain.

This article has been cited by other articles:

• Galbis-Martinez, L., Galbis-Martinez, M., Murillo, F. J., Fontes, M. (2008). An anti-antisigma factor in the response of the bacterium Myxococcus xanthus to blue light. Microbiology 154: 895-904 [Abstract] [Full Text]  
• Stafford, G. P., Ogi, T., Hughes, C. (2005). Binding and transcriptional activation of non-flagellar genes by the Escherichia coli flagellar master regulator FlhD2C2. Microbiology 151: 1779-1788 [Abstract] [Full Text]  
• Perez-Marin, M. C., Lopez-Rubio, J. J., Murillo, F. J., Elias-Arnanz, M., Padmanabhan, S. (2004). The N Terminus of Myxococcus xanthus CarA Repressor Is an Autonomously Folding Domain That Mediates Physical and Functional Interactions with Both Operator DNA and Antirepressor Protein. J. Biol. Chem. 279: 33093-33103 [Abstract] [Full Text]  
• Galbis-Martinez, M., Fontes, M., Murillo, F. J. (2004). The High-Mobility Group A-Type Protein CarD of the Bacterium Myxococcus xanthus as a Transcription Factor for Several Distinct Vegetative Genes. Genetics 167: 1585-1595 [Abstract] [Full Text]  
• Lopez-Rubio, J. J., Padmanabhan, S., Lazaro, J. M., Salas, M., Murillo, F. J., Elias-Arnanz, M. (2004). Operator Design and Mechanism for CarA Repressor-mediated Down-regulation of the Photoinducible carB Operon in Myxococcus xanthus. J. Biol. Chem. 279: 28945-28953 [Abstract] [Full Text]