Plant genetic engineering heavily relies on transgenic technology. For the development of an effective vector system for genetic transformation application well-characterized promoter is crucial. Currently, available promoters are either viral or bacterial origin and hence it is necessary to isolate and analyze additional constitutive promoters of non-viral origin. Plant actin depolymerizing factors (ADFs) have diverse metabolic characteristics however, the majority of biological functions are yet unknown. In this study, we attempted to identify the promoter region of ADF from Plectranthus amboinicus using Arabidopsis thaliana as an internal control by thermal asymmetric interlaced polymerase chain reaction (TAIL PCR). Three heterologous gene-specific primers were designed to isolate the promoter region and the sequences were then examined in silico to check for the presence of minimal promoter elements. Our findings suggested that the TAIL PCR using specific primers is an efficient method for plant promoter isolation. The clone (pTZPaADF) carrying the putative promoter sequence was verified by comparing it with the results obtained for A. thaliana. Alignment of the putative promoter sequences with Arabidopsis revealed the presence of numerous conserved and shared RNA polymerase binding sites. In silico analysis revealed that there were several putative motifs including the TATA and the CAAT boxes. In addition, many other putative cis-acting regulatory elements that may regulate gene expression were also found. Based on the analysis the isolated putative promoter, pTZPaADF, could be employed in driving transgene expression.
Key words: Keywords: Actin depolymerising factor, TAIL PCR, Plectranthus amboinicus, Plant promoter,cis elements
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