Understanding the role of spatial features and canonical binding sites in transcription

he promoter is a key element in genetranscription and regulation. Wepreviously reported that artificial sequen-ces rich in the dinucleotide CpG aresufficient to drive expression in vitro inmammalian cell lines, without requiringcanonical binding sites for transcriptionfactor proteins. Here, we report thatintroducing a promoter organization thatalternates in CpGs and regions rich inA and T further increases expressionstrength, as well as how insertion ofspecific binding sites makes such sequen-ces respond to induced levels of thetranscription factor NFkB. Our findingsfurther contribute to the mechanisticunderstanding of promoters, as well ashow these sequences might be shaped byevolutionary pressure in living organisms.IntroductionThe transcription and regulation of genesis a complex process that, in its basic form,requires the binding of transcriptionfactors (TF) to a promoter region, a se-quence of variable length located upstreamof the transcription start site of a gene.Once bound, these TFs subsequentlyrecruit the transcriptional machinery, lead-ing to the production of primary trans-cripts. Consequently, the interaction ofthe promoter and respective TFs initiallydetermines the strength and timing ofgene expression, and understanding themolecular basis for this interaction hastherefore been subject of much discussionand research.