Fig. 2. Region B of the egl-1 locus is required for the specification of the NSM sister cell death. (A) Schematic representation of the egl-1 locus on linkage group V. pBC119, pBC13, pBC11, pBC149 and pBC165 represent subclones of the egl-1 rescuing fragment pBC08. The abilities of the fragments to rescue NSM sister cell death (see below) are summarized under `Rescue'. The arrow indicates Region B. (B) pBC08, pBC119 and pBC149 can rescue the death of the NSM sister cells in egl-1(lf) animals. Plasmids containing the fragments indicated were introduced by germline transformation into hermaphrodites of genotype egl-1(n1084 n3082) unc-76(e911); lin-15(n765) carrying an integrated P_tph-1gfp reporter construct (bcIs24) as described in the Materials and Methods. Rescue of NSM sister cell death was analysed as described in the Materials and Methods (n=100-240). For every plasmid, several independent transgenic lines were generated and characterized (n=4-7). (C) Region B of the egl-1 locus is highly conserved. Alignment of the sequence of C. elegans Region B (C. elegans sequence VF23B12L bp 2659-2792 and C. elegans cosmid F23B12 bp 1-218) with the sequence of the corresponding region of C. briggsae (C. briggsae cosmid G12D19.2 bp 10590-10248). Identical nucleotides are shaded. The four conserved Snail-binding sites are indicated by boxes.