Fig. 2: Loss of CeSPT-2 histone binding causes germline defects and sterility.

a, Schematic diagram of the WT, spt-2^KO and spt-2^HBM alleles. The genomic location of the spt-2 (T05A12.3) gene on chromosome IV is shown. Colored bars indicate the deleted regions in the spt-2 gene in the KO strains. b, The brood size of worms from the indicated strains, grown at 25 °C from the L4 stage, is shown. Arrows indicate worms with low brood size. The number of worms used is indicated in the figure. c–e, Transgenerational sterility assay (c). Three L4 stage worms of the indicated genotypes were shifted to 25 °C and grown at that temperature for the indicated number of generations. Every generation (3 days), three L3–L4 worms were moved to a new plate. A worm line was considered sterile when no progeny was found on the plate. Ten plates per genotype were used, n = 10. The transgenerational sterility assay was performed using WT, spt-2^KO-A and spt-2^KO-B worms (d), or using WT, spt-2^KO-A, spt-2^KO-B and spt-2^HBM worms (e). f, Diagram of the C. elegans germline (green) and embryos; figure adapted from ref. ³⁸. g–j, Single WT and spt-2^KO-B L4 worms were shifted to 25 °C and grown at that temperature for the indicated number of generations; every generation (3 days), one L4 worm was moved to a new plate and the number of progeny was assessed, as indicated in Extended Data Fig. 2d,e. Siblings of the worms that, 3 days after the L4 stage, showed reduced or no progeny were subjected to microscopic observation 1 day after the L4 stage. Germline from a WT worm (g); germlines from spt-2^KO-B worms, with arrows indicating an abrupt transition between pachytene cells and oocytes (h), mis-localized oocyte (upper arrow) and abnormally small oocyte (lower arrow) (i), and vacuolization (j). k, Quantification of germline defects; numbers indicated in the figure. G_n, number of generations.

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