Auxin-Mediated Sterility Induction System for Longevity and Mating Studies in Caenorhabditis elegans

Abstract

The ability to control both the means and timing of sexual reproduction provides a powerful tool to understand not only fertilization but also life history trade-offs resulting from sexual reproduction. However, precisely controlling fertilization has proved a major challenge across model systems. An ideal sterility induction system should be external, non-toxic, and reversible. Using the auxin-inducible degradation system targeting the spe-44 gene within the nematode Caenorhabditis elegans, we designed a means of externally inducing spermatogenesis arrest. We show that exposure to auxin during larval development induces both hermaphrodite self-sterility and male sterility. Moreover, male sterility can be reversed upon cessation of auxin exposure. The sterility induction system developed here has multiple applications in the fields of spermatogenesis and mating systems evolution. Importantly, this system is also a highly applicable tool for aging studies. In particular, we show that auxin-induced self-sterility is comparable to the commonly used chemically-induced FUdR sterility, while offering multiple benefits, including being less labor intensive, being non-toxic, and avoiding compound interactions with other experimental treatments.

Rapid Degradation ofCaenorhabditis elegansProteins at Single-Cell Resolution with a Synthetic Auxin

“…Caveats of the C. elegans AID system Several recent reports have effectively used the AID system in C. elegans to control protein function, including controlling spermatogenesis by manipulating SPE-44 levels (Kasimatis et al 2018), depleting a mediator component to modulate longevity (Lee et al 2019), examining chromosome segregation during oogenesis (Ferrandiz et al 2018), examining meiotic crossover (Zhang et al 2018), and revealing novel roles of neuronal gene function through conditional depletion (Serrano-Saiz et al 2018). Despite the increasing frequency of AID system usage in the C. elegans community, there are only a handful of TIR1 driver lines published, and the importance of copy number and promoter strength has yet to be systematically assessed.…”

GLP-1 Notch—LAG-1 CSL control of the germline stem cell fate is mediated by transcriptional targets lst-1 and sygl-1

“…Three TIR1 expressing transgenes were tested for efficiency of germine specific removal of LAG-1; TIR1 expressed from the sun-1 promoter [38], the pie-1 promoter [72], or the gld-1 promoter [38]. Efficacy of LAG-1 degradation was assessed by determining the relative mRNA abundance of GLP-1/LAG-1 transcriptional targets, lst-1 & sygl-1, by qRT-PCR, following auxin treatment.…”

The Caenorhabditis elegans Transgenic Toolbox

“…Because auxin can be washed away, the system is also potentially reversible, although restoration to full protein levels may require a lengthy recovery. Like the methods described above, AID can degrade proteins rapidly and has been used to study the loss-of-function phenotype of several different types of proteins (Zhang et al 2015(Zhang et al , 2018bKerk et al 2017;Pelisch et al 2017;Liu et al 2017a;Patel and Hobert 2017;Yu et al 2017;Shen et al 2018;Ferrandiz et al 2018;Kasimatis et al 2018;Serrano-Saiz et al 2018). One potential issue is that addition of the AID degron tag has been reported in a few cases to interfere with function or stability of the tagged protein even in the absence of TIR1 and auxin (Kerk et al 2017;Patel and Hobert 2017;Schmidt et al 2017).…”