Figure 3.

Genomic organization of the racF1 gene. Genomic DNA was digested, and the fragments were resolved on 0.7% agarose gels and blotted onto nylon membrane. Hybridization under stringent conditions was performed with a ³²P-radiolabeled probe corresponding to the coding region of racF1 generated by PCR. Genomic DNA was digested with (1) BglII, (2) EcoRI, (3) EcoRV, (4) HindIII, (5) KpnI, (6) NdeI, (7) PstI, and (8) XbaI. The 1.16-kb HindIII fragment and the 920-bp KpnI fragment used to clone racF1, as well as the 4.4-kb EcoRI fragment used for generation of a knockout vector, can be clearly appreciated. Additional bands visible in every lane indicate the presence of related genes in the Dictyostelium genome. In particular, a 1.6-kb BglII fragment and a 6.6-kb EcoRI fragment probably arise by hybridization to the racF2 gene.