Question

Compare and contrast the cis-acting (DNA) elements found in the promoters of eukaryotes and prokaryotes.

Answer 1

cis acting referring to regulator sequence in DNA ( e.g enhancer, Promoter) that can control a gene only in the same chromosome.

In bacteria cis acting elements are adjacent or proximal to the genes they control

In eukaryotes they may also be far way.

transcription control region : collective term for all the cis acting DNA regulatory sequences that regulate transcription of a particular gene.

cis acting transcrptional regulator elements.

promoter: core promoter, proximal promoter element

distal regulator elements: enhancer, silencers, insulators & locus control regions.

promoter: a combination of short sequence element to which RNA polymerase binds in order to initiate transcription.

EUKARYOTIC CELLS

TATA BOX: a conserved sequence in the promoter of many eukaryotic protein coding genes, where the transcrption- initiation complex assembles located -20~-30 with the sequence of TATAA(T)AA(T).

CAAT BOX: a basal promoter element located -70~-80 with GGC(T)CAATCA.

GC BOX: A type of basal promoter element with GGCGGG which can bind with transcriptional factors Sp1.

PROKARYOTIC CELLS:

-10seq: the consensus sequence centres about 10bp be before the start point of a bacterial gene . it is involved in melting DNA during the initiation reaction.

-35 seq: tthe consensus set centred about 35bp before the start point of a bacterial gene. involved in initial recognition by DNA polymerase.