Gene Regulation in Eukaryotes

Steps of Eukaryotic Gene Expression

1. Chromatin modification (DNA unpacking)

2. Transcription regulation

3. RNA processing (cutting out exons)

4. Degradation of mRNA

5. Degredation of protein

Step 1: Chromatin Modification

what step of eukaryotic gene regulation does this picture represent?

Step 2: transcription regulation (on / off)

what step of eukaryotic gene regulation does this picture represent?

• this is operons in prokaryotes

promoters

DNA sequences upstream of transcription start site

• signals transcriptional start point / initiation

TATA box

an important promoter in DNA is the ?

transcription factors

mediates the binding of RNA polymerase and initiation of transcription

• binds before RNA polymerase binds

rate

transcription factors control the ? of transcription and turns genes on / off

• (GO) activators, enhancers

• (STOP) repressors, silencers

RNA processing (cutting out exons)

translation occurs during Step 3 ?

introns, 5’ GTP cap, 3’ Poly-A tail

during Step 3: RNA modification / processing, ? are spliced out and the ? cap and ? tail are added

5’ GTP Cap

attachment to mRNA that helps ribosomes attach to the mRNA

3’ Poly-A Tail

attachment to mRNA that helps export from nucleus by making RNA stable

protein synthesis, hours, weeks, prevent

during Step 4: Regulation of mRNA degradation, the life span of mRNA can determine the amount of ?

• mRNA can last from ? to ?

• 5’ cap and 3’ tail ? degradation

RNAi (RNA interference)

specific type of RNA that can turn down or shut off specific genes at critical times

• ex: small interfering RNAs (siRNA)

• ex: microRNAs (miRNA)

block, golgi

during Step 5: control of translation / protein processing

• regulatory proteins ? initiation of translation

• ? helps process proteins for transport

• proteins degrade