Nuclear receptors can be grouped into four classes based on their DNA-binding and dimer-ization properties (Fig. 3.4).25 Generally speaking, class I receptors include GRs, mineralcorti-coid receptors (MRs), progesterone receptors (PRs), and androgen receptors (ARs), which function as homodimers and bind to IRs separated by 3 base pairs (i.e., IR-3). An exception to this rule is the estrogen receptors (ERs) which can form either heterodimers or homodimers on IR-3.30-32 Class II receptors require het-erodimerization with RXR family members and bind to DRs, varying from DR-1 to DR-5. The spacing, in general, specifies the identity of the dimerization partner. Class III receptors, including hepatocyte nuclear factor 4 (HNF-4), chicken ovalbumin upstream promoter-transcription factor (COUP-TF), and germ cell nu-
Was this article helpful?
Finally! You Can Put All Your Worries To Rest! You Can Now Instantly Learn Some Little-Known But Highly Effective Tips For Successful Single Parenting! Understand Your Role As A Single Motherfather, And Learn How To Give Your Child The Love Of Both Parents Single Handedly.