Figure 1. Characterization of
shc-1. (A) Alignments of C. elegans SHC-1, human
p52Shc, mouse
p52Shc, and Drosophila DShc. Identical amino acid residues are highlighted, and similar residues are shaded. The conserved PTB and SH2 domains are underlined. (B) Genomic organization of
shc-1 and location of deletion in
ok198. Coding regions are indicated by boxes, and introns are represented as lines. SHC-1 has the N- to C-terminal PTB-SH2 modularity of Shc-like proteins (predicted by SMART, Simple Modular Architecture Research Tool,
http://smart.embl-heidelberg.de). (C) Life-span analysis of
shc-1(
ok198) and rescue by transgenic expression of human
p52shc. All life-span data presented in this and subsequent figures are the result of at least three representative experiments. All life-span data are listed as mean life span ± standard error of the mean; (n) number of animals observed; (Ex) extrachromosomal array; P-values refer to experimental strain and wild-type control animals.
shc-1(
ok198): 8.9 ± 0.1 d (n = 152, P < 0.0001); wild type: 14.4 ± 0.1 d (n = 204);
shc-1(
ok198);Ex[
p52Shc]: 12.0 ± 0.4 d (n = 93, P = 0.1161 vs. Ex[
p52Shc]); Ex[
p52shc]: 12.7 ± 0.3 d (n = 82, P < 0.0001). (D-H)
shc-1::gfp is broadly expressed in C. elegans. SHC-1::GFP stains the pharynx, the majority of head neurons (E), the tail neurons (F), the vulva muscles, and the gonads (G). (H) SHC-1::GFP localizes to both the cytoplasm and nuclei of intestinal cells. A portion of SHC-1 is localized at the cytoplasmic membrane. The image in D was taken with a 20× objective on a Zeiss Axioplan2 microscope using an EGFP filter set (480/20-nm excitation, 510/20-nm emission). To estimate the autofluorescent background signal, we imaged wild-type worms under the same conditions and detected only a faint yellow fluorescence signal in intestinal cells. Bar, 100 μM. (E-H) Higher-magnification pictures were taken on a confocal laser microscope, always showing L4 larvae. Bars: E-G, 50 μM; H, 25 μM.