Fig. 1. Molecular organization of the Fak56 locus and characterization of Fak56^CG1 mutant allele. (A) Schematic comparison of Fak56 with the mammalian FAK family kinases, hsFAK and hsPyk2. Conserved domains are schematized as follows; FERM domain (green), protein tyrosine kinase (PTK) domain (red) and FAT domain (blue). Percentage amino acid identity of FAK domains relative to the Drosophila Fak56 is indicated. (B) Genetic analysis of Fak56. Top panel: the Fak56 locus is depicted together with the surrounding genes (indicated as gray boxes). The arrows below indicate the orientation of Fak56 and the surrounding genes. The location of the P-element insertion used in the excision screen, P{SUPor-P}KG00304 is shown by an inverted triangle. Middle panel: the deduced structure of the approximately 7 kb Fak56 transcription unit is shown in expanded form. The 16 exons are represented by gray boxes. The first AUG initiation codon at the 5' end of the gene is indicated by a flag, and the TAA termination codon at the 3' end is marked by an asterisk. The horizontal gray bars represent the genomic probes employed to identify Fak56 mutants. The FAK I probe corresponds to bp 14-743 and the FAK II probe, bp 2300-3008 (where bp 1 corresponds to the A of the ATG start codon of Fak56). Lower panel: by mobilization of transposon P{SUPor-P}KG00304 373 bp upstream of the Fak56 ATG start codon, deletion Fak56^CG1, which deletes the ATG start codon and eliminates 1263 bp of the Fak56 ORF, including exons 2-5 and a portion of exon 6, was recovered. (C) Mapping of the breakpoints in the Fak56^CG1 chromosome. The sequence alteration in the Fak56^CG1 deletion mutant is flanked by the bases indicated. (D) The 5' region of the Fak56 gene is absent in Fak56^CG1. Genomic DNA from wild-type (1) and Fak56^CG1 (2) flies were probed with FAKI and FAKII (covering 5' and 3' regions of the Fak56 gene respectively), as well as Spt5 (the 5' flanking gene) probes as indicated. Importantly, Southern analysis using the Spt5 probe indicates that this gene is intact in the Fak56^CG1 mutant.