IB 204 - Lecture 11

Codon

a sequence of three DNA nucleotides that encode for an amino acid or stop signal.

Promoter

the region of DNA immediately upstream of a gene where factors necessary to initiate transcription bind.

Terminator

the region of DNA at the end of a gene that contains the information necessary to end transcription by RNA polymerase.

Untranslated region (UTR)

a regulatory region situated at the end of a gene that is transcribed into mRNA but not translated into protein. 5'UTR is upstream of the start codon and the 3'UTR is downstream of the stop codon. They are included in exons as they are a key part of the mature mRNA transcript.

Coding region

the sequence within a gene which encodes for a protein.

Consensus sequence (DNA binding)

a conserved set of nucleotides which are bound by a transcription factor

Transcription factor

a protein which controls the rate of transcription by binding to a DNA sequence

General transcription factor

a protein which helps position RNA polymerase on the promoter.

Transcription bubble

a 12 to 14 bp region of DNA where the double helix is unwound by RNA polymerase to facilitate transcription.

Intron

a segment of DNA which does not encode for proteins and interupts the coding sequence of a gene, it is not included in mature mRNA.

Exon

a region of the genome that is transcribed and included in mature (processed mRNA molecule)

Pribnow box (10 element)

a sequence of six nucleotides TATAAT located upstream of a transcriptional start site in bacteria and bound by a sigma factor

TATA box

a TA rich sequence found in the core promoter of eukaryotic genes bound by the TATA box binding protein.

TFIIB

General transcription factor which binds to the BRE element in the core promoter of eukaryotic genes

TFIID

General transcription factor which is associated with the TATA box binding protein.

TBP

TATA box binding protein, binds to the TATA box helping position RNA polymerase II at the transcription start site.

TFIIH

General transcription factor and component of the preinitiation complex that uses energy from ATP to unwind the DNA double helix.

RNA polymerase II

RNA polymerase that produces mRNA in eukaryotic cells.

Pre-Initiation complex

Complex of proteins including RNA polymerase and general transcription factors that assemble at the promoter of eukaryotic genes

bp

"base pair"

reverse transcriptase

enzyme which catalyzes the synthesis of complementary DNA from an mRNA template