Fig. 5: LAT-1 elicits its effect on germ cells from the DTC.
From: Notch activity is modulated by the aGPCR Latrophilin binding the DSL ligand in C. elegans
a BRET analysis indicates that LAT-1 and LAG-2 establish their interaction on the same cell (cis) (blue line), whereas expression on opposite cells (trans) results in no measurable BRET window (red and yellow lines). n = 4 technical replicates in 2 (setup 1), 2 (setup 2) and 11 (LAT-1 cis) independent experiments. Note that the cis BRET curve is the same as in Supplementary Fig. 7b. b Representative images of gonads from L4 + 8 h-old hermaphrodites with tissue-specific expression of lat-1 in the DTC and germ cells, respectively. Only lat-1 expression in the DTC but not the germ cells resulted in a higher PH3-positive germ cell number and progenitor zone size than in lat-1 mutants, comparable to the wild-type. As a positive control, lat-1 promoter-driven LNT was used that ameliorates the reproductive defects in lat-1 mutants to wild-type levels. Asterisks: DTC, dashed lines: end of the progenitor zone. c Quantification of the progenitor zone (from images shown in (b)). Replicate values (independent experiments): wild-type: 71 (9), lat-1: 53 (12), LNT: 37 (7), lag-2p::lat-1: 46 (7), mex-5p::lat-1: 30 (8). d Quantification of PH3-positive germ cells of images shown in (b). Wild-type 71 (9), lat-1: 53 (12), LNT: 37 (7), lag-2p::lat-1: 46 (7), mex-5p::lat−1: 31 (8). e M index (percentage PH3-positive nuclei from all progenitor zone nuclei). Wild-type 71 (9), lat-1: 53 (12), LNT: 37 (7), lag-2p::lat-1: 46 (7), mex-5p::lat-1: 30 (8). Raw data of PH3-positive cell counts and the denominators for index calculations are given in the Source data. f Proposed model of LAT-1 function. LAT-1 interacts with LAG-2 on the DTC to boost GLP-1 activation in germ cells. This interaction leads to the modulation of gld-1 expression and subsequently, an increase in germ cell proliferation and the regulation of progenitor zone size. Red arrows and lines highlight steps investigated in this study. Graph raw data are provided in the Source Data. Graph details and statistics are: (a): Mean ± SD. (c), (d), (e): Box plots with median (center), interquartal range, 5th (lower whisker) and 95th (upper whisker) percentiles. One-way ANOVA with Bonferroni post-hoc test.
