Mineralocorticoid receptors transcription factors

The corticosteroid receptor in bony fishes is a ligand-dependent transcription factor and recent studies have identified two major classes of CRs, the glucocorticoid receptor and the mineralocorticoid receptor (MR), based on molecular sequences (see below). Here, we summarize studies that have established the receptor characteristics of both these important classes of CRs in fish. 

Fig. 5. Specificity of steroid response element. A. In this example (mouse mammary tumour virus), the element will bind receptors for glucocorticoids (G), androgen (A), progestin (P) and mineralocorticoid (M) so that each of these classes of steroid stimulate transcription. This type of specificity can vary from cell to cell possibly due to other protein factors (not shown). B. Although oestrogen (E) receptor will not act as an agonist for mouse mammary tumour virus transcription, it may antagonise the agonist activity of glucocorticoids (G).

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