CHROMOSOMAL LOCALIZATION OF THE HUMAN DIADENOSINE 5',5'''-P-1,P-4-TETRAPHOSPHATE PYROPHOSPHOHYDROLASE (AP(4)A HYDROLASE) GENE (APAH1) TO 9P13

Diadenosine 5',5'''-P-1,P-4-tetraphosphate (Ap(4)A) hydrolase is the e nzyme responsible for maintaining the intracellular level of the dinuc leotide Ap(4)A, the function of which has yet to be established. The A PAH1 gene encoding this Ap(4)A hydrolase has been mapped by fluorescen ce in situ hybridization and PCR to human chromosome 9p13. Radiation h ybrid panel mapping further located APAH1 between the IL11RA and the G ALT genes, thus excluding it as a candidate gene for cartilage-hair hy poplasia, which maps proximal to GALT. Several tumor suppressor genes have previously been mapped within the 9p13-p21 region. Given that the FHIT gene at 3p14.2, which encodes a diadenosine 5',5'''-P-1,P-3-trip hosphate (Ap(3)A) hydrolase, is a candidate tumor suppressor, APAH1 sh ould also be considered a potential tumor suppressor. (C) 1998 Academi c Press.