proTF: A comprehensive data and phylogenomics resource for prokaryotic transcription factors

Institute of Genomic Medicine/Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou 325035, China.
Bioinformatics (Impact Factor: 4.98). 10/2010; 26(19):2493-5. DOI: 10.1093/bioinformatics/btq432
Source: PubMed


Investigation of transcription factors (TFs) is of extreme significance for gleaning more information about the mechanisms underlying the dynamic transcriptional regulatory network. Herein, proTF is constructed to serve as a comprehensive data resource and phylogenomics analysis platform for prokaryotic TFs. It has many prominent characteristics: (i) detailed annotation information, including basic sequence features, domain organization, sequence homolog and sequence composition, was extensively collected, and then visually displayed for each TF entry in all prokaryotic genomes; (ii) workset was employed as the basic frame to provide an efficient way to organize the retrieved data and save intermediate records; and (iii) a number of elaborated tools for phylogenomics analysis were implemented to investigate the evolutionary roles of specific TFs. In conclusion, proTF dedicates to the prokaryotic TFs with integrated multi-function, which will become a valuable resource for prokaryotic transcriptional regulatory network in the post-genomic era. AVAILABILITY:

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Available from: Jinyu Wu
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    ABSTRACT: Bacterial genes are commonly encoded in clusters, known as operons, which share transcriptional regulatory control and often encode functionally related proteins that take part in certain biological pathways. Operons that are coregulated are known to colocalize in the genome, suggesting that their spatial organization is under selection for efficient expression regulation. However, the internal order of genes within operons is believed to be poorly conserved, and hence expression requirements are claimed to be too weak to oppose gene rearrangements. In light of these opposing views, we set out to investigate whether the internal location of the regulatory genes within operons is under selection. Our analysis shows that transcription factors (TFs) are preferentially encoded as either first or last in their operons, in the two diverged model bacteria Escherichia coli and Bacillus subtilis. In a higher resolution, we find that TFs that repress transcription of the operon in which they are encoded (autorepressors), contribute most of this signal by specific preference of the first operon position. We show that this trend is strikingly conserved throughout highly diverged bacterial phyla. Moreover, these autorepressors regulate operons that carry out highly diverse biological functions. We propose a model according to which autorepressors are selected to be located first in their operons in order to optimize transcription regulation. Specifically, the first operon position helps autorepressors to minimize leaky transcription of the operon structural genes, thus minimizing energy waste. Our analysis provides statistically robust evidence for a paradigm of bacterial autorepressor preferential operonic location. Corroborated with our suggested model, an additional layer of operon expression control that is common throughout the bacterial domain is revealed.
    Full-text · Article · Jun 2011 · Molecular Biology and Evolution