1 / 9

Salivary gland- polytene chromosomes

Same Objective Lens: Why are the salivary gland chromosomes so much larger?. Salivary gland- polytene chromosomes. Alyssa and Tyler. Brain-diploid metaphase chromosomes. MPF (Cdk/Cyclin Protein Complexes) Regulate Progression through Cell Cycle.

ramirezjeffrey
Download Presentation

Salivary gland- polytene chromosomes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Same Objective Lens: Why are the salivary gland chromosomes so much larger? Salivary gland- polytene chromosomes Alyssa and Tyler Brain-diploid metaphase chromosomes

  2. MPF (Cdk/Cyclin Protein Complexes) Regulate Progression through Cell Cycle SKIPPED in Polytene Tissues (Salivary Gland) • MPF= • _________ (Cyclin-dependent Kinase) • - regulates proteins by • phosphorylation • __________ • cell cycle phase- • specific kinase • regulators Cdk Cyclin How might cell cycle regulation differ ? Fig. 14.8

  3. Chromatin: DNA Complexed with Protein 7x compaction Chromatin Packaging in Salivary Gland Squash throughout cell cycle 40x compaction Chromatin Packaging in Metaphase Chromosomes 10,000x compaction 10,000x compaction Fig. 12.12 M phase only

  4. 7x compaction non-heat shocked 40x compaction heat shocked Compaction Level Dark Bands? Light Interbands? 30 nm fiber and higher Lower than 30 nm fiber 10,000x compaction 10,000x compaction Fig. 12.12

  5. Which proteins would you expect to co-localize with HP1 here? HP1 HP1 in transcriptionally silenced centromeric heterochromatin

  6. HP1 binding to Me-K9 histone H3 to silence Transposable Elements in centromeric heterochromatin Fig. 12.17

  7. Nucleosome • ~200 bp DNA wrapped • around histone core • octamer containing • 2 each of 2 different • heterodimers: histones • between • (-) chgd. DNA backbone • and • (20-30% Lys/Arg) • highly conserved amino • acid sequence • packing ratio 7:1 • -sites of • covalent modifications H2A/H2B and H3/H4 ionic bonds (+) chgd. histones N terminal tails Fig. 12.9

  8. N-terminal Covalent Modifications Give a “Histone Code” Acetylation: Deacetylation: Methylation (, K20H4): Heterochromatin Active Chromatin Inactive Chromatin K9H3, K27H3 Fig. 12.14

  9. 7x compaction non-heat shocked 40x compaction heat shocked Bands or Interbands? Acetylated Histones? De-acetylated Histones? Interbands Bands 10,000x compaction 10,000x compaction Fig. 12.12

More Related