The histone acetyltransferase Hat1 facilitates DNA damage repair and morphogenesis in Candida albicans

Abstract

SummaryChromatin assembly and remodelling is an important process during the repair of DNA damage in eukaryotic cells. Although newly synthesized histone H4 is acetylated prior to nuclear import and incorporation into chromatin during DNA damage repair, the precise role of acetylation in this process is poorly understood. Here, we identify the histone acetyltransferase 1 (Hat1) catalysing the conserved acetylation pattern of histone H4 preceding its chromatin deposition in the fungal pathogen Candida albicans. Surprisingly, Hat1 is required for efficient repair of not just exogenous but also endogenous DNA damage. Cells lacking Hat1 rapidly accumulate DNA damages and switch from yeast-like to pseudohyphal growth. In addition, reduction of histone H4 mimics lack of Hat1, suggesting that inefficient H4 supply for deposition into chromatin is the key functional consequence of Hat1 deficiency. Thus, remarkably, we demonstrate that C. albicans is the first organism known to require histone H4 processing for endogenous DNA damage repair and morphogenesis. Strikingly, we also discover that hat1D/D cells are hypersusceptible to caspofungin due to intracellular reactive oxygen species induced by this drug. Hence, we propose that targeting this class of histone acetyltransferases in fungal pathogens may have potential in antifungal therapy.

Genetic interactions among homologous recombination mutants in Candida albicans

“…These observations agree with our suggestion that impairment of an early step on HR or Cse4 deposition/kinetochore assembly triggers growth polarization in C. albicans (Mitra et al, 2014). Filamentation of deletants in histone modifiers hat1 and rtt109 could also be explained by defects in DNA repair or impairment on putative Cse4 modifications which could be needed for its deposition at centromeres (Lopes da Rosa et al, 2010;Mitra et al, 2014;Tscherner et al, 2012). On the contrary, a C. albicans mec1 null mutant, which is impaired in the detection of DNA damage that triggers the DNAdamage checkpoint, is only poorly filamentous (Legrand et al, 2011).…”

“…Growth polarization has also been reported in strains deficient in DNA repair. These include deletion mutants lacking homologous recombination (HR) genes (RAD52, RAD51, and RAD54), exonucleases genes (RAD50 and MRE11) involved in resection of double strand breaks to generate ssDNA, the substrate for Rad51 binding (Andaluz et al, 2006;Hoot et al, 2011;Legrand et al, 2007), or chromatin-modifying genes, such as RTT109 or HAT1 (Lopes da Rosa et al, 2010;Tscherner et al, 2012). Growth polarization in response to genotoxins appears to be mediated by both the DNA-replication and DNAdamage checkpoint pathways, since deletion of effector kinase RAD53 abolishes filamentation (Loll-Krippleber et al, 2014;Shi et al, 2007).…”

The Paralogous Histone Deacetylases Rpd3 and Rpd31 Play Opposing Roles in Regulating the White-Opaque Switch in the Fungal Pathogen Candida albicans

“…These data indicated that this protein might act in concert with Rpd3 to regulate W/O switching. Although sequence comparisons indicated some similarities of orf19.7185 to the acetyltransferase subunit Hat2 of S. cerevisiae (34), the alignment revealed a high conservation with ScUme1 (Fig. 4C).…”

“…All deletion cassettes were constructed by fusion PCR (51) with a fragment containing the selection marker fused to the corresponding upstream and downstream region. Deletion of orf19.7185 in strain J4-2.1 was performed using the linearized plasmid pSFS2A-Ca7185 after digestion with PvuII (34). …”

“…For construction of the C-terminal 9myc and 3-hemagglutinin (3HA) tagging cassettes, the 3′ part of the coding sequence and the terminator region of the corresponding gene were fused with the 9myc and the NAT1 marker amplified from plasmid pFA6a-9myc-NAT1 or 3HA and the SAT1 flipper cassette from plasmid pFA6a-3HA-SAT1-FLP (34). For the reintegration of RPD3 , RPD31 , and truncated RPD31 -T1as well as partial RPD31 -T2 variants into the homozygous deletion mutants, the upstream region with the coding sequence and the terminator region were fused with the SAT1 marker to construct the complementation cassette (15).…”