Linkage of the nuclear hormone receptor genes NR1D2, THRB, and RARB: Evidence for an ancient, large-scale duplication

The THRA gene encoding thyroid hormone receptor alpha shares an unusual par tial overlap with the NR1D1 gene encoding the orphan receptor Rev-ErbA alph a. Though THRA and NR1D1 have close relatives in THRB and NR1D2, which enco de TR beta and Rev-ErbA beta, these beta isoforms do not share an analogous overlap. Here we report that the human THRB and NR1D2 genes are separated by approximately 1 Mb on chromosome 3 and that these two genes are also lin ked to the RARE gene, which encodes retinoic acid receptor beta. Since prev ious results indicate that the THRA/NR1D1 locus is also linked to the RARA gene, these results suggest that the two receptor gene clusters were genera ted by a single large-scale duplication. (C) 1999 Academic Press.