# Endogenous fluorescent reporters for heat shock proteins are not detectable after stress induction

## TL;DR

Researchers tried to create endogenous fluorescent reporters for heat shock proteins in C. elegans but found they couldn't detect the proteins after stress due to low expression.

## Contribution

Generated endogenous reporters for HSP-4 and HSP-60 in C. elegans using CRISPR/Cas9, revealing detection limitations.

## Key findings

- Endogenous reporters for HSP-4 and HSP-60 were successfully created using CRISPR/Cas9.
- GFP induction was not detectable after stress induction, likely due to low expression levels.
- Transgenic reporters may not fully represent endogenous HSP regulation.

## Abstract

Mitochondria and the endoplasmic reticulum (ER) utilise unique unfolded protein response (UPR) mechanisms to maintain cellular proteostasis. Heat shock proteins (HSPs) are UPR chaperones induced by specific stressors to promote protein folding. Previous research has successfully employed transgenic reporters in
Caenorhabditis elegans
to report HSP induction. However, transgenic reporters are overexpressed and only show promoter regulation and not post-transcriptional regulation. To examine endogenous HSP regulation, we attempted to generate and validate endogenous reporters for mitochondrial (
HSP-60
) and ER (
HSP-4
) chaperones. Using CRISPR/Cas9 technology, F2A-GFP-H2B coding DNA was inserted downstream of each HSP gene and stress induction assays conducted to validate these tools. Endogenous reporters were successfully generated for

hsp-4

and

hsp-60

. However, GFP induction could not be detected with these endogenous reporters upon stress induction, likely due to low level expression.