Fig 1. SYGL-1 and LST-1 proteins are spatially restricted to the GSC pool region. (A) Schematic of adult distal gonad. Theprogenitor zone (PZ) includes a distal pool of germline stem cells (GSC) and a proximal pool of cells primed to differentiate [11]. Theconventional metric for axis position is number of germ cell diameters from the distal end (gcd). Somatic niche for GSCs (gray);naive stem cell state (yellow circles); early meiotic prophase (green crescents); primed transiting state (yellow to green gradient).Asterisk marks distal end. (B) Genetic pathway of GSC regulation. (C and D) Schematics of
sygl-1 and
lst-1 loci (top) andtransgenes (bottom). Epitope tagged endogenous alleles are:
sygl-1(
q964)[3xMYC::
sygl-1],
sygl-1(
q983)[3xOLLAS::
sygl-1] andsygl-1
(q1015)[
sygl-1::1xV5];
lst-1(
q1004)[
lst-1::3xV5] and
lst-1(
q1008)[
lst-1::3xOLLAS]. Colored boxes,
sygl-1 or
lst-1 exons; grayboxes, untranslated regions; orange boxes and triangles, epitopes. Bars below schematic, deletions; asterisk, nonsense mutation.See Methods for updated gene structures. (E-J) SYGL-1 and LST-1 proteins in dissected adult gonads. (E-H) Representative sliceor (I-J) maximum intensity z-projections of distal gonad stained with alpha-FLAG (SYGL-1, magenta), alpha-HA (LST-1, yellow), alpha-GLD-1(green), and DAPI (cyan). Dashed line, gonadal outline; asterisk, distal end. Scale bar is 20 um in all images, except 5 um in (E) and(G) insets. (E)
sygl-1(
q828); qSi49[Psygl-1::3xFLAG::
sygl-1::
sygl-1 3'end]. (F)
sygl-1(
q828). (G)
lst-1(
ok814); qSi22[Plst-1::
lst1::1xHA::
lst-1 3'end]. (H)
lst-1(
ok814). See S1A-S1C Fig for whole gonad images. (K and L) Extent of SYGL-1 and LST-1expression along the gonadal axis, estimated with functional epitope-tagged proteins. Expression is robust distally and gradedproximally. Proximal boundaries were estimated by eye as the point at which staining becomes barely detected. nd, not determined.See S1D and S1E Fig for data supporting functionality of epitope-tagged proteins and see S2 Fig for characterization of
sygl-1 orlst-1 mutants.