Practice question

Drosophila Hox genes defined by homeobox encode DNA-binding proteins containing sixty amino acid homeodomain forming three helices inserting into major groove of target enhancers. They function as transcription factors regulating downstream networks rather than executing enzymatic, receptor, or structural roles. Cofactors Extradenticle and Homothorax increase specificity, allowing discrimination between similar AT-rich motifs. Targets include adhesion genes, morphogen modulators, differentiation regulators. Hox factors act combinatorially along axis conferring positional value, maintaining chromatin memory via Polycomb and Trithorax. Therefore classification as transcription factors underscores regulatory hierarchy controlling body plan patterning through gene expression control.