ANT253H1 Lecture 5: Lecture 5 and 6 notes.docx
Document Summary
Transcription elongation in eucaryotes is tightly couples to rna processing: In eucaryotes, transcription"s only the first of several steps needed to produce an mrna; other steps are covalent modifications of rna ends and removal of intron sequences that are discarded from the middle of the. Rna transcript by the process of rna splicing. Somw of these processing proteins hop from the polymerase tail onto the nascent rna molecule to begin processing it as it emerges from the rna polymerase. The ctd is almost 10 times longer than the remainder of the rna polymerase so it serves as a tether holding proteins close by until they"re needed this speeds up the rate of further reactions. Rna polymerase i and iii produce uncapped rnas during transcription because they lack ctd. In nucleus cap binds a protein complex called cbc (cap-binding complex) which helps rna to be properly processed and exported. Rna splicing removes intron sequences from newly transcribed pre-mrnas:
