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 degradationProtects from degradation/ transport 5’ untranslated region 3’ untranslated region

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 Regulation of iron assimilation in mammals: Regulating of Translation

Fig Ferritin 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.

The product of these genes was found to be RNA?

Cell vol. 116, 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 and

A processed mRNA ready for translation: microRNAs inhibit translation by binding to the 3’ end of mRNA microRNA bind to 3’-UTR 5’-UTR 3’-UTR

miRNA expressed miRNA processed to ~22nt RNA Mature miRNA the 3’ end with attached microRNA interacts with the 5’ end, blocking translation Fig 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 , 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

microRNAsiRNA 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 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