Fig. 5. ehn-3 encodes an SGP-specific protein with paired zinc fingers. (A) The ehn-3 locus. cDNA analyses identify three transcripts, each predicted to encode a protein with multiple zinc fingers (black boxes). All cDNAs are transpliced to the SL1 leader. ehn-3A encodes six zinc fingers; ehn-3B1 and B2 encode four zinc fingers. The gene predicted by the sequence consortium, called ZK616.10, corresponds to ehn-3B. ehn-3(q689) is associated with an insertion (T) and a CT transition in exon 2 of ehn-3A. ehn-3(q766) deletes a region including exon 2 from ehn-3A, the next intron and part of the first common exon, including coding sequence for the first 14 amino acids of EHN-3B1 and B2. (B) Semi-quantitative PCR used to assess transcript levels in ehn-3 mutants. (Left) ehn-3 PCR products were less abundant when amplified from ehn-3 mutants than from wild type (lower band in N2 is ehn-3B2); by contrast, hlh-2 PCR product was similar in wild-type and ehn-3 mutants. (Right) Ratio of ehn-3 to hlh-2 PCR products. (C) Alignment of EHN-3 putative zinc fingers. ZNF1-ZNF3 and ZNF6 were predicted by Pfam; ZNF4 and ZNF5 were identified by eye. (D-F) SGP-specific expression of EHN-3::GFP. (D) EHN-3::GFP transgene composition: ehn-3 genomic DNA, including 429 bp of 5' flanking sequence plus the entire EHN-3-coding region, was fused in frame to the GFP-coding sequence. (E) Wild-type embryo expressing EHN-3::GFP. SGP (arrow) has assembled into the gonadal primordium; PGC, asterisk. (F) EHN-3::GFP is expressed in SGP (arrowhead) shortly after gonadal primordium is formed.