Loss of the Transcriptional Repressor PAG-3/Gfi-1 Results in Enhanced Neurosecretion that is Dependent on the Dense-Core Vesicle Membrane Protein IDA-1/IA-2
Figure 4
Increased levels of vesicle proteins in the pag-3(gv650) mutant are dependent on wild type IDA-1 activity.
(A) Complete loss of IDA-1 activity due to the ida-1 null deletion allele ok409 results in a moderate, but significant, reduction in the levels of some vesicle-associated proteins (SNT-1 and RAB-3, *P<0.05) as indicated quantitatively at left and by Western blot signal to the right. All values are given as a percentage of wild type that is arbitrarily set to 100% as indicated by an open box. Error bars indicated variation of individual antibody level. (B) The level of the vesicle cargo component serotonin was compared in HSN neurons by immunofluorescent staining in the indicated four strains. Images show close up of HSN cell body of an adult animal orientated with anterior to the left and dorsal to the top. Exposure times were identical for all images. Scale bar represents 20 µm for all images. (C) The SNT-1 levels were compared by Western blots (shown at top and quantified below) in four different mutant backgrounds as indicated. Note that the increased SNT-1 in gv560 mutants (**, P<0.01) is reduced to wild type levels when the IDA-1 activity is removed in the ida-1(ok409);pag-3(gv560) double mutants. (D) Quantitative analysis of the images show in panel C confirmed that the signal intensity increases seen in the gv560 mutant background are reduced to wild type levels in the ida-1(ok409);pag-3(gv560) double mutants (**, P<0.01). Note that the double mutant levels are not identical to ida-1(ok409), suggesting there may be a small, IDA-1-independent effect of the pag-3 mutation on serotonin.