Overview Function can turn transcription on/off can ↑ or ↓ rate of transcription can act in cis or trans cis = regulation near gene locus login to view 2 more bullets trans = regulation from gene locus login to view 2 more bullets Mechanisms of control modify RNAp binding stability transcription factors login to view 14 more bullets modify RNAp accessibility to DNA histone modifiers login to view 3 more bullets imprinting login to view 6 more bullets inactivation of a chromosome login to view 2 more bullets increase number of gene copies login to view 2 more bullets Embryonic gene regulation sonic hedgehog (SHH) gene mutations causes holoprosencephaly (HPE) login to view 1 more bullet homeobox (HOX) genes control proper timing of gene activation paired box (PAX) genes mutations cause Klein-Waardenburg syndrome login to view 8 more bullets Examples of gene regulation peroxisome proliferator-activated receptors (PPARs) controls fat metabolism login to view 4 more bullets bind PPRE region in DNA clinical importance login to view 2 more bullets