Regulatory Element Analysis and Comparative Genomics Study of Heavy Metal-Resistant Genes in the Complete Genome CR3.

Environmental pollution has become a worldwide concern that requires rigorous efforts from all sectors of society to monitor, control, and remediate it. In environmental pollution control, CR3 has become a model organism to study resistance to heavy metals as a means of bacterial bioremediation. This research aimed to single out regulatory element analysis and conduct a comparative genome study of the heavy metal resistance genes in the complete genome of CR3 using bioinformatics and omics tools. Comparative genome analysis, promoter prediction, common motif identification, transcriptional start site identification, gene annotation, and transcription factor identification search are the major steps to understanding gene expression and regulation. MEME Suit, TOMTOM, Prokka, Rapid Annotation utilizing Subsystem Technology (RAST), Orthologous Average Nucleotide Identity Software Tool (OAT), and EziBio databases or programs were the major tools used in this study. Fourteen transcriptional factors were identified and predicted from the most credible and lowest candidate motifs with an e-value of 3.0e-009, which was statistically the utmost remarkable candidate motif. A detailed evaluation was further performed, and 14 transcriptional factors were identified as in activation, repression, and dual functions. The data revealed that most transcriptional factors identified were used for activation rather than repression. The CR3 genome contains many genes responsible for resisting heavy metals such as mercury, cadmium, zinc, copper, and arsenate. As a result, regulatory elements will lay a solid basis for understanding genes responsible for heavy metal bioremediation. It was concluded that further studies with wet lab support could be conducted for confirmation. Moreover, other advanced bioinformatics and omics technologies are needed to strengthen the results.