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Published byAustin Henderson Modified over 9 years ago
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miRNA miRNA ancient form of regulation. Protection against viral pathogens Quick regulation and turnover of mRNA.
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Drosophila Development: Genetics at work!
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Development of Drosophila
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Closer look at Early Development of Drosophila.
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Cellularization
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Gastrulation and Segmentation
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Anterior-Posterior Polarity in Oocyte Starts during oogenesis Gurken mRNA transferred to oocyte. Signal sent back to oocyte post Gurken/Torpedo interaction. Par-1 mediated organization of microtubules to posterior side of oocyte via Oskar. Minus end (posterior) and plus end (anterior).
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Dorsal-Ventral Patterning in Oocyte.
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Dorsal Gradient
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Anterior-Posterior Polarity in Embryo
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Syncytial Specification in Drosophila
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Anterior-Posterior Polarity in Embryo
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Translational Regulation Stored oocyte mRNAs- selective inhibition of translation. Genes turned on quickly post-fertilization. Relies on the recruitment of proteins involved in making a polyA tail. Drosophila Bicoid gene product.
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Gap Genes Role in early segmentation Transcriptional regulators
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Pair-rule Genes Another set of Transcriptional Regulators. Develops the precursors for the actual segments. Zebra-stripe pattern of expression. Stripe position determined by which enhancer is bound.
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Pair-rule Genes
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Segment Polarity Genes Wingless (Wnt) and Hedgehog signal pathway proteins. Paracrine signaling maintains segmentation.
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Homeotic Selector Genes (Hox) Regulated by Pair-rule and Gap genes. Antennapedia Complex and bithorax complex. AbdA and AbdB repressed by Hunchback and Kruppel. Repression maintained by Polycomb, activation maintained by Trithorax.
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Epigenetic Memory Trithorax- keeps genes active. Counteract Polycombs Modify nucleosomes Keep H3K4 trimethylated Polycomb- keeps genes inactivated. H3K27 methylase Bind meH3 tails
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Hox Genes in Other Species Mouse Limb development- deletion of Hoxd11, Hoxd12, Hoxd13 causes polydactyly Zebra fish, loss of H3K27 demethylase activity and subsequent Hox gene disregulation- poor tail development
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