Figure 1.
flp-1 deletion alleles. (A) Genetic position of
flp-1 on the right arm of chromosome IV. (B) Genomic organization of
flp-1. Top line: partial restriction map of the
flp-1 genomic region. E, Eco RI; C, Cla I. Bottom line: Expanded genomic region to show organization of
flp-1. Exons are indicated as boxes (peptide coding sequences are indicated in black), introns as lines; the site of the Tc1 insertion is indicated by an inverted triangle. Two deletions of the
flp-1 gene were isolated by PCR screening of populations of Tc1 insertion strains for an imprecise Tc1 excision (13). The extent of the
yn2(1.4 kbp) and
yn4 (2.1 kbp) deletions are shown; both deletions remove upstream and coding regions. Primers used to screen for deletions are indicated by arrows. (C) Backcrossed
yn2 and
yn4 strains are homozygous deletion lines. Genomic DNA was isolated from backcrossedyn2 and
yn4 animals, digested with Cla I, and Southern blotted. The position of the probe is shown in (B). Solid arrow indicates wild-type hybridizing fragment; double arrows indicate smaller hybridizing fragments resulting from the
yn2 andyn4 deletions. No hybridizing fragment corresponding to the wild-type fragment is detected in DNA from homozygous
yn2and
yn4 animals. Molecular weight markers (kilobase pairs) are indicated to the left. (D) Expression offlp-1 in wild-type animals is detected only in anterior head neurons. Transgenic animals were stained for beta-galactosidase activity to visualize expression of
flp-1-lacZ reporter constructs (10). Scale bar, 25 um.