Rolland, Stephane et al. (2022) MicroPubl Biol

Conradt, Barbara, Rolland, Stephane

[MicroPubl Biol, 2022]

The mitochondrial unfolded protein response (UPR mt ) is an important stress response that ensures the maintenance of mitochondrial homeostasis in response to various types of cellular stress. We previously described a genetic screen for Caenorhabditis elegans genes, which when inactivated cause UPR mt activation, and reported genes identified that encode mitochondrial proteins. We now report additional genes identified in the screen. Importantly, these include genes that encode non-mitochondrial proteins involved in processes such as the control of gene expression, post-translational modifications, cell signaling and cellular trafficking. Interestingly, we identified several genes that have been proposed to participate in the transfer of lipids between peroxisomes, ER and mitochondria, suggesting that lipid transfer between these organelles is essential for mitochondrial homeostasis. In conclusion, this study shows that the maintenance of mitochondrial homeostasis is not only dependent on mitochondrial processes but also relies on non-mitochondrial processes and pathways. Our results reinforce the notion that mitochondrial function and cellular function are intimately connected.

Memar, Nadin et al. (2022) MicroPubl Biol

Memar, Nadin, Sethi, Aditya, Conradt, Barbara, Luehr, Sebastian, Lambie, Eric J

[MicroPubl Biol, 2022]

Visualization of genomic loci with open chromatin state has been reported in mammalian tissue culture cells using a CRISPR/Cas9-based system that utilizes an EGFP-tagged endonuclease-deficient Cas9 protein (dCas9::EGFP) (Chen et al. 2013). Here, we adapted this approach for use in Caenorhabditis elegans . We generated a C. elegans strain that expresses the dCas9 protein fused to two nuclear-localized EGFP molecules (dCas9::NLS::2xEGFP::NLS) in an inducible manner. Using this strain, we report the visualization in live C. elegans embryos of two endogenous repetitive loci, rrn-4 and rrn-1 , from which 5S and 18S ribosomal RNAs are constitutively generated.

Conradt B et al. (1999) Cell "The TRA-1A sex determination protein of C. elegans regulates sexually dimorphic cell deaths by repressing the egl-1 cell death activator gene."

Horvitz HR, Conradt B

[Cell, 1999]

The hermaphrodite-specific neurons (HSNs) of the nematode Caenorhabditis elegans are generated embryonically in both hermaphrodites and males but undergo programmed cell death in males. The gene egl-1 encodes a BH3-containing cell death activator that is required for programmed cell death in C. elegans. Gain-of-function (gf) mutations in egl-1 cause the inappropriate programmed cell death of the HSNs in hermaphrodites. These mutations lie 5.6 kb downstream of the egl-1 transcription unit and disrupt the binding of the TRA-1A zinc finger protein, the terminal global regulator of somatic sexual fate. This disruption results in the activation of the egl-1 gene in the HSNs not only in males but also in hermaphrodites. Our findings suggest that in hermaphrodites TRA-1A represses egl-1 transcription in the HSNs to prevent these neurons from undergoing programmed cell death.AD - Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02319, USA.FAU - Conradt, BAU - Conradt BFAU - Horvitz, H RAU - Horvitz HRLA - engID - GM24663/GM/NIGMSPT - Journal ArticleCY - UNITED STATESTA - CellJID - 0413066RN - 0 (DNA, Helminth)RN - 0 (EGL-1 protein)RN - 0 (Helminth Proteins)RN - 0 (Luminescent Proteins)RN - 0 (Oligodeoxyribonucleotides)RN - 0 (Repressor Proteins)RN - 0 (TRA-1A protein)RN - 0 (Transcription Factors)RN - 147336-22-9 (green fluorescent protein)SB - IM