Final answer:
B. Have ligand-binding and DNA-binding domains, and can directly bind to DNA.
Nuclear receptors typically have ligand-binding and DNA-binding domains. They may be located in the cytoplasm or nucleus, bind to various ligands including hormones, and regulate gene transcription by directly interacting with DNA.
Step-by-step explanation:
The question is about the characteristics of nuclear receptors. Nuclear receptors are a class of proteins within cells that are responsible for sensing steroid and thyroid hormones and certain other lipids. They have a common mechanism of action that involves directly regulating the expression of target genes.
All nuclear receptors are not the same, but they typically share some key features.
Importantly, they:
- Have ligand-binding and DNA-binding domains, and can directly bind to DNA.
- Can be located in the cytoplasm or in the nucleus before ligand binding.
- Often change conformation upon ligand binding and can enter the nucleus from the cytoplasm if they are not already there.
- Bind to steroid and thyroid hormones among other ligands.
- Function as transcription regulators, acting as repressors or activators depending on the presence of ligand.
Therefore, the most accurate statement regarding nuclear receptors is that they have ligand-binding and DNA-binding domains, and can directly bind to DNA (option B).