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more regulating gene expression. 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
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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 16.1
Fig 23.25 Alternate Splicing in Drosophila Sex Determination
Fig 23.25 Alternate splicing leads to sex determination in fruit flies
mRNA transport is an important regulatory step Molecular Biology of the Cell 4th ed. Alberts et al. Fig 6.40 http://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 7.52 http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.TOC&depth=2
At least 3 mechanisms are involved: Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.98 Directed transport via cytoskeleton Random diffusion and trapping Degradation and local protection
A processed mRNA ready for translation 5’ untranslatedregion 3’ untranslatedregion Protects from degradation/ recognition for ribosome Protects from degradation/ transport to cytoplasm
mRNA with 3’ UTR properly localized mRNA without 3’ UTR improperly localized Molecular Biology of the Cell 4th ed. Alberts et al. Fig 7.99 http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.TOC&depth=2
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 16.1
Fig 15.25 Regulation of iron assimilation in mammals: Regulating of Translation
Fig 15.26 Ferritin is regulated at translation
C. elegans mutants with cells that do not develop properly. The product of these genes was found to be RNA?
MicroRNAs (miRNA) are ~22nt RNAs that play important regulatory roles Cell vol. 116, 281-297 2004
miRNA expressed How do microRNAs control gene expression? 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’-UTR 3’-UTR
miRNA expressed the 3’ end with attached microRNA interacts with the 5’ end, blocking translation miRNA processed to ~22nt RNA Mature miRNA 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
tissue specific expression of mouse microRNA PNAS vol. 101 #1 pg 360-365, 2004
Gene Expression is controlled at all of these steps: • DNA packaging • Transcription • RNA processing and transport • RNA degradation • Translation • Post-translational Fig 16.1
Phosphorylation and dephosphorylation of proteins can change activity
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
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
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