Assignment of a novel bifurcated SET domain gene, SETDB1, to human chromosome band 1q21 by in situ hybridization and radiation hybrids

We have identified a human gene encoding an unusual bifurcated SET domain p rotein containing a large "insertion" between the most highly conserved par ts of the SET domain. The existence of an evolutionarily related C. elegans gene encoding a similarly bifurcated SET domain suggests that SET domains may generally be composed of two functionally distinct subdomains. We mappe d this gene, called SETDB1, to human chromosome 1q21. This region is target ed by a large number of recurrent translocations, suggesting that like the SET domain protein MLL, mutant forms of SETDB1 may be associated with human neoplasias.