Kurhanewicz, N. A. | bioRxiv Science

bioRxiv2025

WAGO-1 is a sexually dimorphic Argonaute protein required for proper germ granule structure and gametogenesis

Germ cell proliferation and proper genome inheritance are critical for maintaining fertility through generations. To promote proper germ cell development, small RNA pathways employ Argonaute proteins (AGOs) to modulate gene expression and protect against deleterious genomic elements while not silencing against self. Here we identify sexual dimorphisms in localization and function of protein structural features of the Argonaute WAGO-1 that affects sex-specific gene regulation during C. elegans germ cell development. During meiotic prophase I progression, we find that germ granule structural proteins and the PIWI AGO, PRG-1, display dynamic and distinct localization patterns between egg and sperm development which coincide with differential WAGO-1 localization and biophysical properties. Sexually dimorphic functions of specific WAGO-1 protein structural domains underpin these differences. Disruption or modification to the N-terminus intrinsically disordered region (IDR) of WAGO-1 leads to loss of PGL-1 phase separation only during spermatogenesis. Further, we find that these germ granule disruptions are likely due to prolonged association of the IDR with the RNA-binding pocket of WAGO-1. In addition, deletion of the MID and part of the PIWI domains causes male-specific sterility and disruption to WAGO-1 localization with PGL-1 during oogenesis. Finally, we demonstrate that these disruptions to WAGO-1 protein structure dynamically change the mRNA and sRNA landscape of adult males and hermaphrodites, in which the AGOs ALG-3/4 and VSRA-1 are misregulated. Together, these data suggest that WAGO-1 differentially regulates genes during oogenesis versus spermatogenesis, and that these differences in gene regulation may be due to the sex-specific configuration and biophysical properties of WAGO-1 within the germ granule.

developmental biology↗

bioRxiv2020

Automated and customizable quantitative image analysis of whole C. elegans germlines

Arranged in a spatial-temporal gradient for germ cell development, the adult germline of Caenorhabditis elegans is an excellent system for understanding the generation, differentiation, function, and maintenance of germ cells. Imaging whole C. elegans germlines along the distal-proximal axis enables powerful cytological analyses of germ cell nuclei as they progress from the pre-meiotic tip through all the stages of meiotic prophase I. To enable high-throughput image analysis of whole C. elegans gonads, we developed a custom algorithm and pipelines to function with image processing software that enables: 1) quantification of cytological features at single nucleus resolution from immunofluorescence images; and, 2) assessment of these individual nuclei based on their position within the germline. We demonstrate the capability of our quantitative image analysis approach by analyzing multiple cytological features of meiotic nuclei in whole C. elegans germlines. First, we quantify double strand DNA breaks (DSBs) per nucleus by analyzing DNA-associated foci of the recombinase RAD-51 at the single-nucleus resolution in the context of whole germline progression. Second, we quantify the DSBs that are licensed for crossover repair by analyzing foci of MSH-5 and COSA-1 when they associate with the synaptonemal complex during meiotic prophase progression. Finally, we quantify P-granule composition across the whole germline by analyzing the colocalization of PGL-1 and ZNFX-1 foci. Our image analysis pipeline is an adaptable and useful method for researchers spanning multiple fields utilizing the C. elegans germline as a model system.

cell biology↗