Methylation of DNA strands can serve to distinguish parent (template) strands from newly synthesized strands in E. coli DNA

TLS Online TPP Program

#Id: 1985

#Unit 3. Fundamental Processes

Binding of the capping enzyme to the TFIIH mediated serine 5–phosphorylated CTD stimulates the activity of the enzyme.

TLS Online TPP Program

#Id: 1986

#Unit 3. Fundamental Processes

RNA polymerases I or III do not have a CTD so no capping is stimulated

TLS Online TPP Program

#Id: 1987

#Unit 3. Fundamental Processes

The 5’ cap of most mRNA is monomethylated, but some small noncoding RNAs are trimethylated.

TLS Online TPP Program

#Id: 1988

#Unit 3. Fundamental Processes

Small ncRNAs involved in RNA splicing in the spliceosome are trimethylated at terminal guanine. This structure is called a trimethylated cap. The enzymes for these additional methyl transfers are present in the cytoplasm.

TLS Online TPP Program

#Id: 1989

#Unit 3. Fundamental Processes

SL RNA (Trans-splicing) carries a trimethylated cap, which is recognized by the variant cap-binding factor eIF4E to facilitate translation.

TLS Online TPP Program

#Id: 1990

#Unit 3. Fundamental Processes

The sequence AAUAAA (hexamer) is a signal for cleavage to generate a 3’ end of mRNA that is polyadenylated.