Homeodomain binding proteins have one helix in DNA major groove and another helix across DNA that contacts other proteins. Fruitfly homeotic genes {homeobox gene} control head, jaws, teeth, thorax, and abdomen development and contain 180-base control regions {homeobox} that have helix-turn-helix {homeodomain} sequences, which are in many development genes. Regulatory region has 200,000 bases total.
retinoic acid
Extracellular-fluid retinoic acid controls homeotic-gene expression by binding to cell receptors and builds spinal cord, hindbrain, eye, and limbs. Low concentrations start gene expression at forebrain, and then higher concentrations start gene expression in sequence down to tail.
hormone
Thyroid hormone has similar receptors and controls gene expression.
Biological Sciences>Genetics>Gene>Development>Homeobox Gene
4-Genetics-Gene-Development-Homeobox Gene
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0224