Figure 2.
bnc-1 Is a Class-Specific Regulator of Motor Neuron Identity(A)
unc-129 is expressed in DA/DB MNs (class member neurons within the white bounding rectangle are magnified in the inset on the right) and is regulated byunc-3. In
ot721 and
ot763 animals (which do not complement each other),
unc-129 is derepressed in VA/VB MNs in an
unc-3-dependent manner. This phenotypeis rescued by the genomic locus of a novel C. elegans gene,
bnc-1 (basonuclin 1). All scale bars represent 50 um. WT, wild type.(B) Quantification for (A); error bars show the SD. Unpaired t tests were performed for all mutants compared to WT. ***p < 0.001 (n R 13).(C)
bnc-1 gene locus.(D) BNC-1 protein and its orthologs.(E) Endogenous
bnc-1 locus tagged with mNG shows remarkably specific expression in VA/VB MNs (except for VB1) in the VNC (see Figure S4A for additionalexpression elsewhere). Gut auto-fluorescence (asterisk); stitched together from two images of the same worm, showing the anterior half of the worm.(F)
bnc-1 cDNA driven by an
unc-3 promoter in DA/DB/VA/VB MNs in
bnc-1 mutants rescues the
unc-129 derepression phenotype in VA/VB and is sufficient toectopically repress
unc-129 in DA/DB MNs. WT image repeated from (A); red pharyngeal expression marks the
unc-3prom::
bnc-1 transgene.(G) Expression of the
unc-3-dependent class-specific effector genes
unc-53 (DA/AS),
unc-8 (DA/DB/AS), and
acr-16 (DB) is derepressed in VA/VB MNs of
bnc-1mutants.(H) Quantification for (G); error bars show the SD. Superimposed diagonal stripes indicate dim expression. Unpaired t-tests were performed for all mutantscompared to WT. ***p < 0.001 (n R 13).(I) Genetic model depicting BNC-1 repressing DA/DB-specific effector genes in VA/VB MNs.