602

chapter 26

Regulation of Gene Expression

T A B L E 2 6 -4

Promoter and Enhancer Controlling Elements and Transcription Factors That Bind to Them

Consensus Sequence*

Response Element

Factor

TATA AAA

TATA Box

TFIID

GGCCAATCT

CAAT Box

CTG/NF1

GGGCGG

GC Box

SP1

ATTTGCAT

Octamer

Octl, Oct2

CNNGAANNTCCNNG

HSE

Heat shock factor

TGGTACAAATGTTCT

GRE

Glucocortoid receptor

CAGGGACGTGACCGCA

TRE

Thyroid receptor

CCATATTAGG

SRE

Steroids

*Consensus sequence is for either a promoter or enhancer element. The letter N stands for any nucleotide (A,G, C,T).

H,N

COOH

Helix - loop - helix

F IG U R E 2 6 -7

Structures of transcription factors that facilitate binding to DNA at specific sequences to regulate gene expression.