Eukaryotic Transcription 真核生物的转录
Eukaryotic Transcription 真核生物的转录
Key Concepts Differences between Prokaryotes and Eukaryotes Three kinds of rna polymerases(, Il, and IID) in eukaryotic cells Promoters and enhancers Upstream regulatory elements Transcription factors
Key Concepts • Differences between Prokaryotes and Eukaryotes • Three kinds of RNA polymerases (I, II, and III) in eukaryotic cells • Promoters and Enhancers • Upstream regulatory elements • Transcription factors
Similarities to that in prokaryotic cells Don t require a primer Synthesize rna in a 5 to 3 direction RNa complementary to the antisense template strand
Similarities to that in prokaryotic cells • Don’t require a primer • Synthesize RNA in a 5’ to 3’ direction • RNA complementary to the antisense template strand
Differences between Prokaryotes and Eukaryotes There are 3 RNa polymerases Require more accessory factors for binding promoter dna initiating transcription The C-terminus of rna Pol Ii largest subunit contains a stretch of heptapeptide repeats, named as carboxyl terminal domain (CTD) Amino acid sequence: Tyr-Ser-Pro-Thr-Ser-Pro-Ser. Repeated 26X (yeast)& 52x in mouse Involved in polymerase phosphorylation during elongation The CTd is unphosphorylated at transcription initiation, and phosphorylation occurs during transcription elongation as the RNa Pol II leaves the promoter (In vitro results) Because it transcribes all eukaryotic protein-coding gene, RNA Pol II is the most important rna polymerase for the study of differential gene expression. The Ctd is an important target for differential activation of transcription elongation
Differences between Prokaryotes and Eukaryotes • There are 3 RNA polymerases • Require more accessory factors for binding promoter DNA & initiating transcription • The C-terminus of RNA Pol II largest subunit contains a stretch of heptapeptide repeats, named as carboxyl terminal domain (CTD) • Amino acid sequence: Tyr-Ser-Pro-Thr-Ser-Pro-Ser. Repeated 26 x (yeast) & 52x in mouse • Involved in polymerase phosphorylation during elongation • The CTD is unphosphorylated at transcription initiation, and phosphorylation occurs during transcription elongation as the RNA Pol II leaves the promoter(In vitro results) • Because it transcribes all eukaryotic protein-coding gene, RNA Pol II is the most important RNA polymerase for the study of differential gene expression. The CTD is an important target for differential activation of transcription elongation
Key Terms a basal factor is a transcription factor required by RNa polymerase Il to form the initiation complex at all promoters. Factors are identified as TFIX whereⅩ is a number The basal transcription apparatus is the complex of transcription factors that assembles at the promoter before Rna polymerase is bound An enhancer is a cis-acting sequence that increases the utilization of(some)eukaryotic promoters, and can function in either orientation and in any location (upstream or downstream) relative to the promoter
Key Terms • A basal factor is a transcription factor required by RNA polymerase II to form the initiation complex at all promoters. Factors are identified as TFIIX, where X is a number. • The basal transcription apparatus is the complex of transcription factors that assembles at the promoter before RNA polymerase is bound • An enhancer is a cis-acting sequence that increases the utilization of (some) eukaryotic promoters, and can function in either orientation and in any location (upstream or downstream) relative to the promoter