Regulating Gene Expression from RNA to Protein

Fig 16.1

Gene Expression is controlled at all of these steps:•DNA packaging•Transcription•RNA processing and transport•RNA degradation•Translation•Post-translational

Fig 15.1

A processed mRNA ready for translation

Protects from degradation Protects from degradation/ transport

5’ untranslatedregion

3’ untranslatedregion

Fig 16.1

Gene Expression is controlled at all of these steps:•DNA packaging•Transcription•RNA processing and transport•RNA degradation•Translation•Post-translational

Fig 15.1

Seeds germinated underground begin growing in darkness then emerge into light and begin photosynthesis

energy from seed

energy from sun

The level of this mRNA increases after plants are exposed to light.

•How might the cell accomplish this?

The level of this mRNA increases after plants are exposed to light.

•How might the cell accomplish this?Increased transcription and/or decreased mRNA degradation

Northern blot analysis: The level of this mRNA increases after plants are exposed to light.

•How might the cell accomplish this?•Does this necessarily lead to increased protein production?

Fig 16.1

Gene Expression is controlled at all of these steps:•DNA packaging•Transcription•RNA processing and transport•RNA degradation•Translation•Post-translational

Fig 15.1

Fig 15.25

Regulation of iron assimilation in mammals:Regulating of Translation

Fig 15.26Ferritin is regulated at translation

C. elegans is commonly used to study development

C. elegans development

C. elegans mutants with cells that do not develop properly.

C. elegans mutants with cells that do not develop properly.

The product of these genes was found to be RNA?

Cell vol. 116,281-297 2004

MicroRNAs (miRNA) are ~22nt RNAs that play important regulatory roles

How do microRNAs control gene expression?

miRNA expressed

miRNA processed to ~22nt RNA

Mature miRNA

Fig 15.23 and

A processed mRNA ready for translation:microRNAs inhibit translation by binding to the 3’ end of mRNA

microRNA bind to 3’-UTR

5’-UTR3’-UTR

miRNA expressed

miRNA processed to ~22nt RNA

Mature miRNA

the 3’ end with attached microRNA interacts with the 5’ end, blocking translation

Fig 15.23 and

miRNAs can lead to methylation of DNA that

leads to inhibition of transcription

microRNAs primarily target gene products that function during development

Tbl 1

PNAS vol. 101 #1 pg 360-365, 2004

tissue specific expression of mouse microRNA

Silencing RNAs (siRNA) are artificially induced dsRNA

Fig 15.21

siRNA with exact matches to the target mRNA causes degradation of the mRNA

microRNA siRNA

Translation inhibited mRNA degraded

Fig 16.1

Gene Expression is controlled at all of these steps:•DNA packaging•Transcription•RNA processing and transport•RNA degradation•Translation•Post-translational

Phosphorylation and dephosphorylation of proteins can change activity

Ubiquitinization targets proteins for degradation

All protein interactions in an organism compose the interactome

Some proteins function in the cytoplasm; others need to be transported to various organelles.

How can proteins be delivered to their appropriate destinations?

Fig 13.23

Proteins are directed to their destinations via signals in the amino acid sequence

Protein Destinations: secretion or membrane

• Signal sequences target proteins for secretion

Translation of secreted proteins

Translation of membrane bound proteins

Translation of secreted or membrane bound proteins

This step determines secretion or membrane bound.

Protein Destinations: nucleus Signal anywhere in protein, Translation in cytoplasm,Signal not removed

Protein Destinations: mitochondria or chloroplast

Signal translated first, Translation in cytoplasm, Signal removed

Protein Destinations: signals in protein determine destination

Tbl 13.8

Development: differentiating cells to become an organism