SKN-1 isoform-c is essential for C. elegans development

Abstract

The transcription factor SKN-1 in Caenorhabditis elegans is a critical regulator of various biological processes, impacting development, diet and immune responses, cellular detoxification, and lipid metabolism; thereby playing a pivotal role in regulating the health and lifespan of the organism. The primary isoforms of SKN-1 ( SKN-1 a, SKN-1 b, and SKN-1 c) exhibit distinct functions resembling mammalian Nrf transcription factors. This study investigates the specific role of the SKN-1 c isoform in development by generating mutants with targeted missense mutations in the skn-1 c and skn-1 a isoforms. The skn-1 c Met1Ala mutants, which replaces a start methionine with alanine, renders SKN-1 c non-functional while preserving other isoforms, produced inviable embryos, requiring a balancer chromosome for proper embryonic development. In contrast, skn-1 a Met1Ala mutants, which replaces the start methionine with alanine for this isoform, displayed normal embryonic development and hatching. Moreover, the data suggest that SKN-1 c plays a crucial role in embryonic development, as strains without maternally deposited SKN-1 c lead to embryos that are developmentally arrested. Together, these findings contribute to our understanding of SKN-1 c's specific role in influencing embryogenesis and development in C. elegans.

Figure 1. SKN-1 isoform c is essential for embryonic development

( A ) Schematic of skn-1 isoforms marking the location of the skn-1 a Met1Ala (“no A”) and skn-1 c Met1Ala (“no C”) mutations. ( B ) Quantification of percentage of plates that have viable progeny on them after 72 hours. ( C ) Quantification of embryonic development of embryos 15 hours post-egg lay. Percent of population categorized into 3 groups: less than 1.5-fold (blue), greater than 1.5-fold (red), and larval stage 1 (green). ( D-E ) Imaging of embryos derived from parents of the indicated genotypes ( skn-1 a Met1Ala, skn-1 c Met1Ala, or skn-1 ( ok2315 ) ); nT1 balancer harbors an integrated GFP marker to follow presence of the element.