more regulating gene expression

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 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 23.25

Alternate Splicing in Drosophila Sex Determination

Alternate splicing leads to sex determination in fruit flies

Fig 23.25

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 6.40http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.TOC&depth=2

mRNA transport is an important regulatory step

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.52http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.TOC&depth=2

mRNA can be localized to a specific parts of a cell (from Drosophila embryo)

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.98

At least 3 mechanisms are involved:

Directed transport via cytoskeleton

Random diffusion and trapping

Degradation and local protection

A processed mRNA ready for translation

Protects from degradation/ recognition for ribosome

Protects from degradation/ transport to cytoplasm

5’ untranslatedregion

3’ untranslatedregion

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.99http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.TOC&depth=2

mRNA with 3’ UTR properly localized

mRNA without 3’ UTR improperly localized

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 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

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

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

Next: Development- differentiating cells to become an organism