Control of gene expression

Where does gene expression need to be regulated

• Chromatin- methylation

• Transcription

• RNA processing

• Degrading mRNA

• Translation

• Post translation

What are housekeeping genes

Genes which code for proteins which are always required

What is chromatin

• DNA wrapped around histones to form chromatin, DNA is negatively charged and histones are positively charged

• DNA can be tightly wound (heterochromatin) or loosely wound (euchromatin)

What is chromatin remodelling

• During cell division DNA is in form of heterochromatin and euchromatin during interphase

What is histone modification

• Acetylation- addition of acetyl groups reduces histones positive charge so DNA is coiled less tightly so RNA polymerase can access DNA

• Methylation- addition of methyl groups makes histones more hydrophobic so bind more tightly therefore DNA coils more tightly so RNA polymerase cannot access genes

What are transcription factors

Proteins which bind to promotor region of a gene to regulate rate of transcription they can upregulate= activators or downregulate= repressors