Figure 1. The
egg-1 Gene, Related Proteins, Expression, and Subcellular Localization. (A)
egg-1 genomic structure and the
tm1071 mutation. The position of the trans-spliced leader (SL1), the start ATG, and proposed site of GLD-1 translational repressor regulation in the 3' untranslated region (UTR) are indicated. The bracket below indicates the sequences deleted in
tm1071. The position of primers used for PCR amplifications in (B) are indicated and labeled P1 and P2.(B) PCR characterization of the
tm1071 deletion mutation shows that the band amplified with primers P1 and P2 is smaller from
tm1071 homozygotes than from wild-type. These PCR products were sequenced to further verify the nature of this mutation.(C) Visual comparison of the structural organization of the EGG proteins with each other and the worm LDL receptor homolog RME-2 and the human LDL receptor. The percent amino acid identity between EGG proteins is indicated with brackets. Protein motifs are indicated in the boxed key.(D-K) Expression pattern and subcellular localization of EGG-1:GFP (D, F, and G), EGG-2:GFP (E, H, and I), and RME-2:GFP (J and K). The expression of EGG-1:GFP (D) and EGG-2:GFP (E) in the adult gonad and developing oocytes is shown. (F and G) Deconvolved images showing the subcellular localization of EGG-1:GFP ([F], middle focal plane; [G], 10 focal plane stack projection of the cell surface), EGG-2:GFP ([H], middle; [I], surface), and RME-2:GFP ([J], middle; [K], surface/cortex). The tight localization of EGG-1/EGG-2:GFP to the plasma membrane is very different from that of RME-2 which accumulates in cortical endosomes at a steady-state [13].