PQN-75 is expressed in the pharyngeal gland cells of C aenorhabditis  elegans and is dispensable for germline development

Abstract

In Caenorhabditis elegans, five pharyngeal gland cells reside in the terminal bulb of the pharynx and extend anterior processes to five contact points in the pharyngeal lumen. Pharyngeal gland cells secrete mucin-like proteins thought to facilitate digestion, hatching, molting and assembly of the surface coat of the cuticle, but supporting evidence has been sparse. Here we show pharyngeal gland cell expression of PQN-75, a unique protein containing an N-terminal signal peptide, nucleoporin (Nup)-like phenylalanine/glycine (FG) repeats, and an extensive polyproline repeat domain with similarities to human basic salivary proline-rich pre-protein PRB2. Imaging of C-terminal tagged PQN-75 shows localization throughout pharyngeal gland cell processes but not the pharyngeal lumen; instead, aggregates of PQN-75 are occasionally found throughout the pharynx, suggesting secretion from pharyngeal gland cells into the surrounding pharyngeal muscle. PQN-75 does not affect fertility and brood size in C. elegans but confers some degree of stress resistance and thermotolerance through unknown mechanisms.

P-hydroxybenzaldehyde protects Caenorhabditis elegans from oxidative stress and β-amyloid toxicity

“…However, when resisting the hypoxic stress response, the relative expression of this protein is reduced, thus slowing the aging process ( Kaufman et al, 2017 ), which is similar to our findings, and suggests that p -HBA can slow down the aging process by resisting hypoxic stress. PQN-75 is expressed in pharyngeal gland cells of C. elegans , and studies have shown that it protects the organism from acute temperature changes and has a protective effect on the high-temperature-induced stress response ( Rochester et al, 2017 ). Thus, the up-regulation of PQN-75 expression after administration of p -HBA suggests that p -HBA helps to resist high-temperature stress injury.…”