CMMB 403 Lecture Notes - Lecture 27: Neural Tube, Neural Plate, Neural Groove
5 Jan 2019
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Neural tube formation and patterning part 1. No hox genes are expressed in rhombomere 1 (which forms the cerebellum) A knockout of hoxa2 causes an expansion of rhombomere 1 identity to the posterior. So posterior cells transformed to a more anterior identity. Hox genes not expressed in forebrain and midbrain. As you progress down, there are anterior limitations in the posterior-expressing cells. Notice: the most anteriorly expressed is hoxa2 in the neural tube only hox gene expressed in rhombomere 2 (exception to collinearity. No more hox genes expressed further than the most anterior limit of hoxa2. In general, hox lof causes anterior structures to form in a posterior location. Hox gof (mis-expression in a more anterior domain than usual) causes posterior structures to form in a more anterior location. Organogenesis happens between 4th to 8th week of development for humans. During this, rudiments of all the organ systems are formed. Neural tube derivatives: the cns (spinal cord and brain)
