Fig. 5

Lrp13 mediates the heat stress response mechanism of vitellogenic oocyte formation in zebrafish. a Gross anatomical appearance and histological analysis of lrp13-/- zebrafish mutants and heterozygous controls (+/-) at 120 days post-fertilization (dpf) under normal (28 °C) and high (33 °C) temperatures. PG, primary growth follicle; PV, previtellogenic follicle; EV, early vitellogenic follicle; FG, full-grown follicle; sc, stroma cells; Y, yolk. b Percentage of ovarian degeneration occurrence. Statistical significance was determined using two-sided Fisher’s exact test. c Relative ovary size in different groups of zebrafish (n = 3 fish). Bars represent the mean ± SD. Statistical significance was determined by one-way ANOVA with Tukey’s test. d qPCR-based quantification of lrp1aa expression levels in different groups of zebrafish (n = 3 fish). Relative gene expression level was expressed as fold change compared to lrp13 + /- heterozygous controls reared at 28 °C. Bars represent the mean ± SEM. Statistical significance was determined by one-way ANOVA with Tukey’s test. e Co-IP assay demonstrating the interaction between the Vtg1-LPD_N domain and the Lrp1aa-LBD1 domain in zebrafish. The red arrowhead indicates the target band. Representative results from three independent experiments are shown. f H3K27ac signal intensity in the lrp1aa gene and lrp1aa expression levels in different zebrafish groups. Horizontal bars below the signals indicate enriched regions identified by MACS2. H3K27ac peaks identified in lrp13-/- zebrafish mutants with normal ovaries reared at 28 °C, but absent in other groups, were indicated by gray rectangles. g Schematic illustrating the compensatory role of Lrp1aa in the absence of Lrp13 in zebrafish. Under normal conditions, Lrp13 primarily mediates Vtg absorption, while Lrp1aa compensates for its loss by upregulating expression. High temperatures suppress lrp1aa expression, whereas Lrp13 remains unaffected by heat stress, ensuring Vtg absorption and protecting vitellogenic oocyte formation under elevated temperatures. P values are indicated above the plots, with P < 0.05 considered statistically significant. Source data are provided as a Source Data file.