Comparative study of cis-regulatory elements in the promoter regions of calcineurin B-like genes (CBLs) of Aeluropus, Arabidopsis and rice plants

The calcineurin B-like protein (CBL) is an essential calcium sensor that plays a crucial role in plant growth, development and stress responses. The identification of a cis-acting element in the promoter region of the CBL gene family in three plants, including Oryza sativa (OsCBL), Arabidopsis thaliana (AtCBL), and Arabidopsis littoralis (AtCBL), was investigated because of their importance and involvement in signal transduction under abiotic and biological stresses. Sub-cellular localization of 10 AtCBL, 10 OsCBL and six AlCBL genes showed that AtCBL4, AtCBL10, AlCBL4.2, AlCBL4.3 and AlCBL10 proteins were located in the plasma membrane. 26 CBLs were identified and grouped into two major groups based on their orthologous relatedness in the phylogenetic tree. According to a comparative analysis of the gene structure of the CBLs gene family, about 66 percent of AlCBL genes, 60 percent of AtCBL genes, and 80 percent of OsCBL genes had eight exons and seven introns. Cis-regulatory elements were identified and grouped into eight distinct classes. The ABRE, ARE, GC motif, MBS, DRE, STRE, and LTR motifs were essential stress-related elements. Different regulatory mechanisms in the promoter region of AtCBLs are responsible for their distinct expression patterns, which are regulated by numerous tissue-specific and stress-specific cis-elements. The functional analysis of AlCBL4.2 (which contains six as-1 motifs) will provide useful information about this gene's regulatory processes due to its tissue-specific and enhancer feature of as-1 motif.