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).
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.
Gap Genes Role in early segmentation Transcriptional regulators
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.
Segment Polarity Genes Wingless (Wnt) and Hedgehog signal pathway proteins. Paracrine signaling maintains segmentation.
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.
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