Figure 1. Mutations in E2 ubiquitin-conjugating enzyme genes and
glr-1 affect spontaneous reversal frequencies differently: A. Spontaneous reversal frequency assays were performed using wild type (WT) C. elegans, alongside strains harboring mutations in
glr-1 or in genes that encode the E2 ubiquitin-conjugating enzymes,
ubc-6 and
ubc-7. Box and whisker plots show the average reversals per minute, bounded by quartiles; the line in each box represents the median of the average reversals per minute for each genotype. N=20 individual animals for all genotypes; significance relative to WT was calculated using the Tukey-Kramer test following a one-way ANOVA (*, p=0.0027 for
glr-1; non-significant: p=0.58 for
ubc-6; p=0.48 for
ubc-7). The data is normally distributed (Shapiro-Wilk test, p=0.86) and groups show equal variance (residuals vs. fitted plot). B. Schematics of E2 ubiquitin-conjugating enzyme genes and
glr-1 gene, including the locations of point mutations. Schematics were made using
http://wormweb.org/exonintron. C. Crystal structures of the human E2 Ube2j2 (top, with rotated view to show the back side of the protein) and Ube2g2 (bottom, left). Models were made using Pymol. Residues that are mutated are shown in red (Ube2j2, D153; UBC-6, T158) and yellow (Ube2g2, P78, UBC-7, P79). Residue F156 of Ube2j2 is shown in cyan. Alignments of C. elegans UBC-6 and UBC-7 regions of homology, compared to putative orthologs in other eukaryotes. The highlighted residues correspond to those shown in the structures.