Molecular cloning of a novel member of the nuclear receptor superfamily related to the orphan receptor, TR2.

We have cloned a novel member (mTR2R1) of the nuclear receptor superfamily of transcription factors from a mouse brain cDNA library. The cDNA sequence predicts a protein primary structure of 629 amino acids with a calculated molecular weight of 68.8 kDa. The amino acid sequence of the protein contains three regions of consensus sequence that are conserved throughout the nuclear receptor superfamily. One of these regions encodes a type II zinc finger DNA binding domain that is characteristic of this family of transcription factors. Comparison of the amino acid sequence of mTR2R1 with other nuclear receptors indicates that it is most closely related to the orphan receptor, hTR2, and suggests that these proteins constitute a novel subfamily within the nuclear receptor superfamily. mTR2R1 is encoded by two mRNAs that show different but overlapping spatial patterns of expression in the adult mouse. The identification of a subfamily of TR2 receptors together with the existence of variant mRNAs for these receptors prompts a close examination of the tissue-specific regulatory role of this subfamily of nuclear receptors.