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Biology subjects

Chetty, M.

Publications and source records attributed to Chetty, M..

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Post-inference Methods Of Prior Knowledge Incorporation In Gene Regulatory Network Inference

The regulatory interactions in a cell control cellular response to environmental and genetic perturbations. Gene regulatory network (GRN) inference from high-throughput gene expression data helps to identify unknown regulatory interactions in a cell. One of the main challenges in the GRN inference is to identify complex biological interactions from the limited information contained in the gene expression data. Using prior biological knowledge, in addition to the gene expression data, is a common method to overcome this challenge. However, only a few GRN inference methods can inherently incorporate the prior knowledge and these methods are also not among the best-ranked in benchmarking studies.\n\nWe propose to incorporate the prior knowledge after the GRN inference so that any inference method can be used. Two algorithms have been developed and tested on the well studied Escherichia coli, yeast, and realistic in silico networks. Their accuracy is higher than the best-ranking method in the latest community-wide benchmarking study. Further, one of the algorithms identifies and removes wrong interactions predicted by the inference methods. With half of the available prior knowledge of interactions, around 970 additional correct edges were obtained and 1300 wrong interactions were removed. Moreover, the limitation that only a few GRN inference methods can incorporate the prior knowledge is overcome. Therefore, a post-inference method of incorporating the prior knowledge improves accuracy, removes wrong edges, and overcomes the limitation of GRN inference methods.

systems biology

RegCyanoDB: a database of cyanobacterial regulatory interactions

BackgroundCyanobacteria are photoautotrophic organisms with environmental, evolutionary, and industrial importance. Knowledge of its regulatory interactions are important to predict, optimise, and engineer their characteristics. However, at present, very few of their regulatory interactions are known. The regulatory interactions are known only for a few model organisms such as Escherichia coli due to technical and economical constraints, which are unlikely to change soon. Thus, mapping of regulatory interactions from well-studied organisms to less-studied organisms by using computational techniques is widely used. Reverse Best Hit (RBH), with appropriate algorithm parameters, is a simple and efficient method for detecting functional homologs.\n\nDescriptionWe predict the regulatory interactions in 30 strains of cyanobacteria using the known regulatory interactions from the best-studied organism, E. coli. RBH method with appropriate parameters is used to identify the functional homologs. An interaction is mapped to a cyanobacterial strain if functional homologs exist for a known transcription factor and its target gene. The confidence of the detected homologs and interactions are also provided. Since RBH is a conservative method, homolog-grouping is performed to recover lost putative interactions. A database of the predicted interactions from all the 30 strains of cyanobacteria is constructed.\n\nConclusionRegcyanoDB contains 20,280 interactions with confidence levels for 30 cyanobacterial strains. The predicted regulatory interactions exhibit a scale free network topology as observed in model organisms. The interacting genes in E. coli and cyanobacteria are mostly found to have the same gene annotation. This database can be used for posing novel hypotheses and validation studies in wet-lab and computational domains.\n\nThe database is available at http://www.che.iitb.ac.in/grn/RegCyanoDB/

bioinformatics