Chapter 13: Gene Transcription

uracil

what does RNA have instead of thymine?

-OH on 2’ carbon

what makes RNA less stable?

single-stranded and complementary regions leading to secondary structures

what gives RNA its functional diversity?

transcription

copying a specific segment of DNA (a gene) into a complementary messenger RNA (mRNA) molecule

rNTPs, DNA template, and RNA polymerase

what ingredients do we need to make RNA?

5’ to 3’

in what direction does transcription move?

coding strand

DNA strand with the same 5' to 3' sequence as the transcribed mRNA

template strand

the specific single-stranded DNA sequence that acts as a blueprint for synthesizing complementary molecules’ 3’ to 5’

transcription unit

DNA template + sequences necessary for its transcription

promoter

DNA sequence recognized and bound by transcription apparatus; indicates which strand in temple, direction of transcription, and TSS

RNA-coding region

DNA sequence that gets transcribed into RNA

terminator

sequence of nucleotides that indicate where transcription ends

initiation, elongation, and termination

what are the stages of transcription?

initiation

transcription apparatus recognizes and binds to promoter, transcription bubble forms, the fist bonds between rNTPs are made, and the transcription apparatus leaves the promoter

elongation

DNA is threaded through RNA polymerase, and RNA is synthesized in a 5’ to 3’ manner

termination

end of transcription unit is recognized, RNA separates from DNA template

consensus sequences

similar and highly conserved sequences that serve an important function like protein binding

sigma factor

target RNA polymerase to the right spot

topoisomerases

relieve strain associated with DNA unwinding and rewinding in transcription

RNA polymerase stops synthesizing DNA, RNA is released from RNA polymerase, new RNA molecule dissociated from DNA template, and RNA polymerase detaches from DNA template

how does transcription terminate?

polycistronic mRNA

multiple genes transcribed together with one terminator

acetyltransferases

add acetyl groups to amino acids on the ends of histones, which destabilizes nucleosome structure and makes DNA more accessible

chromatin-remodeling proteins

can bind to chromatin and replace nucleosomes

3

how many RNA polymerases do eukaryotes have?

RNA polymerase II

transcribes genes that encode proteins; has a core promoter and a regulatory promoter

accessory proteins

bind to promoter and recruit a specific RNA polymerase

general transcription factors

contribute to the basal transcription apparatus

basal transcription apparatus

assembles near start site and can initiate minimum levels of transcription

transcriptional activator proteins

bind to DNA in regulatory promoters/enhancers and bring about higher transcription levels

core promoter

where does the basal transcription apparatus bind?

rate of transcription

what does the regulatory promoter contribute to?