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Salivary Gland Polytene Chromosomes Rapid Embryogenesis- 10 minute - - PowerPoint PPT Presentation
Salivary Gland Polytene Chromosomes Rapid Embryogenesis- 10 minute - - PowerPoint PPT Presentation
Salivary Gland Polytene Chromosomes Rapid Embryogenesis- 10 minute cycles Variations in the cell cycle during Drosophila development Canonical S G1 G2 No gaps No mitosis M Imaginal tissues (adult eyes, wings, etc.) S S Posters 350B
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Variations in the cell cycle during Drosophila development
Canonical S M G2 G1
Imaginal tissues
(adult eyes, wings, etc.) Adult nurse cells Larval tissues
S G No mitosis S M No gaps
Early embryos Posters 350B 340A
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Unregulated DNA replication and Absence of mitosis in png, plu, or gnu mutants
wild type png, plu, or gnu mutant
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early late
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The PNG kinase is inactive!
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PNG, PLU, and GNU form an active protein kinase complex
PNG GNU
P P
P
P P
PLU
P P P P
PNG- ser/thr protein kinase PLU- 19kDa ankyrin repeat protein, activating subunit GNU-27kDa protein; promotes dimerization and activation
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PNG, PLU, GNU [Cyclin B] / CDK1
DNA Replication Chromosome condensation Mitosis
Translation
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Is PNG required to inhibit PUM repression of cycli lin B translation throughout the embryo?
PNG GNU PLU png mutant No Translation
cyclin B 3’UTR
? PUM ? PUM
PNG GNU PLU
cyclin B 3’UTR
Translation
Does removal of PUMILIO in a png mutant restore translation?
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Mutations in pum umil ilio io suppress the png331
331 8 mutant
phenotype
png3318 pum/+ png3318 pum png3318 pum tubulin DNA
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M
Maternal- Zygotic Transition PNG Kinase
S
PUM Cyclin B SMG Deadenylation mRNA deg.
Tadros et al.
- Dev. Cell 12,
143 (2007)
Transition from Meiosis to Embryonic Mitosis
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Primary Arrest Prophase I Secondary Arrest Metaphase I Completion
- f meiosis as
egg passes through
- viduct
Adapted from Xiang et al. PLoS Biol 5(12): e323
Oocyte Maturation Egg Activation
Meiosis in Female Drosophila
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Analysis of Protein Changes at Egg Activation
Adapted from: Xiang Y et al., PLos Biol, 2007
- Quantitative proteomic analysis of proteins that
increase or decrease at activation
- Polysome profiling-identify all mRNAs recruited or
released from polysomes
Iva Kronja Poster 174C
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3500 proteins scored in replicates 132 proteins upregulated at egg activation 230 proteins downregulated at egg activation (Zach Whitfield- Talk #10 today)
Proteomics Results
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Mature Oocyte (stage 14) Activated Egg
Downregulated Proteins-mRNAs move off polysomes Polysome Profiling Results- 5300 mRNAs analyzed Upregulated Proteins-mRNAs move from monosome to polysomes
Mature Oocyte (stage 14) Activated Egg
5’ 5’ 5’ 5’ 3’ 3’ 3’ 3’
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Mature Oocyte (stage 14) Activated Egg
Downregulated Proteins Role of PNG in Translation at Egg Activation Upregulated Proteins
Mature Oocyte (stage 14) Activated Egg PNG Dependent Largely PNG Independent
3’ 3’ 3’ 3’ 5’ 5’ 5’ 5’
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PNG serves to activate translation generally at the developmental transition from oocyte to embryo
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- Pursue biological problems in unbiased way.
- Generosity of the community in providing
resources.
- Application of varied approaches including
high throughput.
- Drosophila is an amazing model organism
with many more exciting problems to solve.
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Fay Shamanski Myles Axton Debbie Burney-Sigman Janet Carminati Lisa Elfring Doug Fenger Helena Kashevsky Laurie Lee Leah Vardy Masatoshi Hara Iva Kronja (Poster 174C)
PNG and PLU
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