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20 Cards in this Set
- Front
- Back
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Homeotic genes |
Establish what is each segment going to make |
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Bicoid mRNA |
Produced by nurse cells, secreted in anterior Translated to bicoid protein Represses translation of caudal Protein gradient generates caudal gradient in syncytial blastoderm Translation factor |
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Caudal genes |
Even distribution of mRNA Repressed in anterior Translated in posterior Transcription factor |
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Hunchback maternal mRNA |
Evenly distributed, bicoid activates its translation Anterior gap gene |
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Nanos mRNA |
secreted by nurse cells with scaffold protein for transportation to posterior Blocks translation of hunchback |
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Acron Telson |
Terminal section of the head including brain Posterior tail regions |
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Ternimal determinant - torso |
Ovarian follicle cells make torso like protein at both ends- activates torso protein Activates terminal gap genes Torso is a RTK |
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Expression of gap genes is regulated by |
Bicoid and Hunchback gradients and Interations between gap genes |
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Pair rule genes |
Concentration of gap proteins determine transcription Increased definition throughout development Ftz and eve - pair rule genes that make up even and odd gaps |
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Segment polarity genes |
Controlled by ftx and eve Activated after cellular blastoderm formation Mediate interactions between cells Set segment boundries - permanent Wingless and engrailed |
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Parasegments then segments |
Nerves formed first and go through parasegment boundries, muscles are formed later within segemental boundries |
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Segment specific homeotic genes |
Act as transcription factors Hox genes - selectors, construction of segment specific traits Eg) antp - legs, expressed in the thorax, turned off in the head Locations and development similar across species |
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Hox genes contd. |
Organized in clustersm 5-3 polarity order of gene cluster matters Othewise homeotic transformations (legs for antenna) |
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Realisator genes |
Controlled by homeotic genes to form tissues and organs Eg) hox can bind to realisator genes to repress growth of eyes where legs should be Mutations when inhibitors cant bind to silencer |
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Dorsal ventral polarity is established by |
Gurken and dorsal |
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Gurken |
dorsal ligand bade by oocyte, interacts with follicular cells |
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Dorsal |
ventral transcription factor Translocation from cytoplasm to ventral nuclei 14th division |
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Dorsal ventral polarity |
1. oocyte nucleus travels to anterior dorsal side of oocyte 2. Gurken translated, recieved by Torpedo protein 3.Torpedo causes follicle cells to differentiate dorsal morphology, synthesis of pipe is inhibited only on this side 4. gurken does not diffuse to ventral side |
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Amount of dorsal |
determins % of dorsalization (ventralization) Large amount - mesoderm Small amount - glial or ectodermal |
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Dorsalized mutant Ventralized mutant |
dorsal cannot get into nuclei dorsal goes everywhere |
