lecture: regulation of gene expression - eukaryotes - AWS

LECTURE: REGULATION OF GENE EXPRESSION - EUKARYOTES KIRSTIN BROWN

Lecture: REGULATION OF GENE EXPRESSION - part 2 Outline:

1. Overview 2. Histone modifications 3. Transcription factors

Overview Gene expression can be regulated at different levels:

Protein

DNA

Protein modification

Chromatin remodeling

Translation Transcription splicing

mRNA

Overview Eukaryotes do not have operons o They regulate groups of genes involved in the

same processes by:

➢ Chromatin remodeling ➢ Transcription factors

Histone Modification Eukaryotes remodel their chromatin to make genes accessible o Adding methyl groups to histone proteins causes them to pack tightly together – DNA inaccessible to RNA polymerase o Adding acetyl groups to histone proteins

causes them to pack loosely together – DNA accessible to RNA polymerase

Transcription Factors Regulation of transcription through binding of activators or repressors o Most eukaryotic genes have sequences upstream of the promoter which bind transcription factors

Transcription Factors Gene regulation is in response to environmental ques o Signal transduction mediates the repsonse Cell membrane

Nucleus

ADP ATP ADP ATP

ADP

ATP

Transcription