BIOL 4330 1st Edition Lecture 5 Outline of Last Lecture I. Morphogen GradientsII. CleavageIII. Cell Movement PatternsIV. Sea UrchinsV. DrosophilaOutline of Current Lecture I. Drosophila ContinuedII. Gap GenesIII. Early Anterior-posterior Axis SpecificationCurrent LectureGap genes enable the expression of pair rule genes divide the embryo into segments. Three independentgenetic pathways interact to form the anterior-posterior axis of the Drosophila embryo.Anterior- posterior specification originates from morphogen gradients in the egg cytoplasm.Summary of early anterior-posterior axis specification 1) Genes that define the anterior organizing center. Anterior organizing center (located at the anterior end) acts through a gradient of Bicoid protein- Bicoid functions as a TF to activate anterior-specific gap genes and as a translational repressor to suppress posterior-specific gap genes. 2) Genes that define posterior organizing center. Posterior organizing center (located at the posterior pole) acts translationally trough the Nanos protein to inhibit anterior formation, and transciptionally through the Caudal protein to activate genes that form the abdomen. 3) Genes that define the terminal boundary regions. The boundaries of the acron and telson are defined by the product of the torso gene, activated at the embryo tips.The Drosophila embryo has uncovered numerous genes that are responsible for the specification of the anterior-posterior and dorsal-ventral axes. We donʼt know it all yet, but mutations have revealed much about the multiple levels of pattern regulation in a complex organism and have enabled us to isolate these genes and their products.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Drosophila genes provide clues to the general mechanism of pattern formation that is used throughout the animal
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