Mapping of an ordered set of 14 cosmids to human chromosome 12p by two-color in situ hybridization.

To map human chromosome 12p aberrations by fluorescence in situ hybridization (FISH), cosmids were isolated or obtained for 14 known 12p loci (D12S119, D12S158, D12S178, D12S370, D12S380E, A2M, CACNL1A1, FGF6, GAPD, KRAS2, PRB1, PZP, TPI1, and VWF). Using two-color FISH with three labeled probes to interphase nuclei, and to prometaphase chromosomes where possible, the order of these loci was sequentially determined to be pter-D12S158-D12S380E-CACNL1A1-FGF6- D12S370-VWF-GAPD-TPI1-A2M-PZP-PRB1-D12S 178-D12S119-KRAS2-cen. Two cell lines were analyzed with this set of cosmids. The EBV-transformed cell line TA carries a der(12) with a deletion of bands 12p13.1-->p11.2.D12S178, D12S119, and KRAS2 were absent in the der(12), whereas the other loci were present. The second cell line, GM01203A, exhibits a balanced t(4;12)(4q25; 12p13.3) with a breakpoint between FGF6 and D12S370.