THSC/TREX-2 deficiency causes replication stress and genome instability in Caenorhabditis elegans.

Angelina Zheleva,María García-Rubio,Andrés Aguilera,Lola P Camino,Nuria Fernández-Fernández,Tatiana García-Muse,Peter Askjaer

doi:10.1242/jcs.258435

Abstract

Transcription is an essential process of DNA metabolism, yet it makes DNA more susceptible to DNA damage. THSC/TREX-2 is a conserved eukaryotic protein complex with a key role in mRNP biogenesis and maturation that prevents genome instability. One source of such instability is linked to transcription, as shown in yeast and human cells, but the underlying mechanism and whether this link is universal is still unclear. To obtain further insight into the putative role of the THSC/TREX-2 complex in genome integrity, we have used Caenorhabditis elegans mutants of the thp-1 and dss-1 components of THSC/TREX-2. These mutants show similar defective meiosis, DNA damage accumulation and activation of the DNA damage checkpoint. However, they differ from each other regarding replication defects, as determined by measuring dUTP incorporation in the germline. Interestingly, this specific thp-1 mutant phenotype can be partially rescued by overexpression of RNase H. Furthermore, both mutants show a mild increase in phosphorylation of histone H3 at Ser10 (H3S10P), a mark previously shown to be linked to DNA-RNA hybrid-mediated genome instability. These data support the view that both THSC/TREX-2 factors prevent transcription-associated DNA damage derived from DNA-RNA hybrid accumulation by separate means.

Highlights

Defects in the coupling of transcription with mRNA processing and export results in DNA damage and genome instability (Gaillard et al, 2013; Gómez-González and Aguilera, 2019)
C.elegans THSC/TREX-2 complex is essential for fertility To analyze the role of THSC/TREX-2 in C. elegans, first we performed a search of THSC/TREX-2 orthologs based on the sequence comparison (Garcia-Oliver et al, 2012)
Failures of DNA metabolism processes such as DNA replication and repair are a major source of DNA damage accumulation in cells (Aguilera and Garcia-Muse, 2013)

Summary

INTRODUCTION

Defects in the coupling of transcription with mRNA processing and export results in DNA damage and genome instability (Gaillard et al, 2013; Gómez-González and Aguilera, 2019). The THSC/TREX-2 complex is conserved from yeast to humans and is involved in mRNP biogenesis (Garcia-Oliver et al, 2012; Rondón et al, 2010) It interacts with the nuclear pore complex (NPC) and is constituted by the stable association of the multi-domain protein Sac3/GANP with the Thp1/PCID2, Sus1/ENY2, Cdc31/CEN2 and Sem1/DSS1 subunits (Fischer et al, 2002; Gallardo et al, 2003; Lei et al, 2003), among which Cdc and Dss have been characterized as a centrin and a 19S proteosome subunit, respectively (Faza et al, 2009; Fischer et al, 2004; Wilmes et al, 2008). This study highlights that cells have developed alternative ways to avert DNA-RNA hybrids and minimize their incidence as a source of DNA damage and genome instability

RESULTS

DISCUSSION

MATERIALS AND METHODS