"Syntheticpromoters A promoter assembled by combining various primary elements required for the definedpromoter function may be referred to as a synthetic promoter. The various elements used insuch a promoter are, usually, of diverse origin. Among these elements the TATA box, thetranscription start site or cap site, and the CCAAT consensus sequence are required foraccurate constitutive transcription. A synthetic promoter may be either constitutive tissue- specific or inducible, depending on the functional sequences used in its construction. Theselection, copy number and spacing of cis-regulatory elements determine the strength,temporal and spatial expression patterns of synthetic promoters.Strategies for designing synthetic promoters:Several approaches have been used togenerate synthetic promoter.Cis-motif engineering has been used to manipulate the position,spacing and the number of key cis-elements. Recent advances in bioinformatics tools havefacilitated the design of highly specific synthetic promoters capable of driving geneexpression in a tightly regulated manner.? Chimeric promoter? Site-directed mutagenesis? Shuffling? Bidirectional promoter? Linker-scanning mutagenesis Types of Synthetic promoters Biotic stress-inducible synthetic promotersAbiotic stress- inducible synthetic promotersLight-responsive synthetic promotersChemical-responsive synthetic promotersHormonal responsive synthetic promotersSynthetic promoters with constitutive expressionTissue-specific synthetic promoters Advantages of synthetic promoters over core promoters? Higher expression level with high specificity? Lower basal expression? Shorter length? Less sequence homology to any host genomic DNA.References: "