Homework #2 is due 10/17 Bonus #1 is due 10/24 Office hours: M 10/ :30am 2-5pm in Bio 6

Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 6.40 mRNA transport is an important regulatory step

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.52 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’ untranslated region 3’ untranslated region

Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.99 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

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

C. elegans is commonly used to study development

C. elegans development

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

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

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

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 8.22

siRNA with exact matches to the target mRNA causes degradation of the mRNA Fig 8.21

microRNAsiRNA Translation inhibited mRNA degraded

Fig 8.19

Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational

Homework #2 is due 10/17 Bonus #1 is due 10/24 Office hours: M 10/ :30am 2-5pm in Bio 6