Final answer:
The DNA-binding domain is responsible for the interaction of intracellular receptors with responsive elements in the nucleus. It attaches to hormone response elements on the promoter DNA to regulate gene expression. Receptors like those for thyroid hormones act as hormone-activated transcription factors through this domain.
Step-by-step explanation:
The domain of intracellular receptors that binds to responsive elements in the nucleus is the DNA-binding domain. This domain recognizes and attaches to specific sequences of promoter DNA known as hormone response elements. Intracellular receptors belong to a larger group of nuclear receptors, including those for thyroid and steroid hormones. These receptors function as hormone-activated transcription factors, playing a crucial role in modulating gene expression by interacting directly with the DNA within the nucleus.
One example of such interaction is the zinc-finger region of the DNA-binding domain, essential for the receptor to precisely attach to the response element necessary for the regulation of gene transcription. Mutations within this domain can impair the receptor's ability to bind DNA without necessarily affecting other functions of the receptor, like binding the hormone or the dimer formation with another receptor.
Moreover, the ligand-binding domain of the receptor is responsible for the recognition and binding of the specific hormone and facilitating the dimerization of the receptor, essential for intracellular signaling pathways and consequent gene regulation. However, it is the DNA-binding domain that directly interacts with the DNA to commence transcriptional processes.