文献类型：期刊文献

英文题名：A three-gene cluster in Trichoderma reesei reveals a potential role of dmm2 in DNA repair and cellulase production

作者：Cai, Wanchuan[1];Chen, Yumeng[1];Zhang, Lei[1];Fang, Xu[2];Wang, Wei[1]

机构：[1]East China Univ Sci & Technol, New World Inst Biotechnol, State Key Lab Bioreactor Engn, 130 Meilong Rd,POB 311, Shanghai 200237, Peoples R China;[2]Shandong Univ, State Key Lab Microbial Technol, Sch Life Sci, Jinan, Peoples R China

年份：2022

卷号：15

期号：1

外文期刊名：BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS

收录：;EI(收录号：20221411912602);WOS:【SCI-EXPANDED(收录号:WOS:000775074700001)】；

基金：The project was funded by the Natural Science Foundation of Shanghai, China (No. 22ZR1417600), the National Natural Science Foundation of China (32000050), and Shanghai Agriculture Applied Technology Development Program, China (Grant No. 2021-02-08-00-12-F00758).

语种：英文

外文关键词：Trichoderma reesei; DNA methylation modulator-2; tku70; Hem8; dmm2; Ferrochelatase; Cellulase

摘要：Background The ascomycete Trichoderma reesei is one of the most efficient industrial producers of cellulase. Gene targeting by homologous recombination is a key technique for improving strains and constructing mutants. In T. reesei, tku70 (homologous to human KU70) was deleted to block non-homologous end-joining, which led to 95% of transformants exhibiting homologous recombination. Results Two genes located in close proximity to tku70 were identified: the ferrochelatase gene hem8 (tre78582, homologous to Aspergillus niger hemH and Cryptococcus neoformans HEM15) and a putative DNA methylation modulator-2 gene dmm2 (tre108087, homologous to Neurospora crassa dmm-2). Genome-wide surveys of 324 sequenced fungal genomes revealed that the homologues of the three genes of interest are encoded in tandem in most Sordariomycetes. The expression of this three-gene cluster is regulated by blue light. The roles of these three genes were analyzed via deletion and complementation tests. The gene hem8 was originally described as a novel and highly distinct auxotrophic marker in T. reesei and we found that the product protein, HEM8, catalyzes the final step in heme biosynthesis from highly photoreactive porphyrins. The lethal phenotype of the hem8 deletion could be overcome by hematin supplementation. We also studied the functions of tku70 and dmm2 in DNA repair using mutagen sensitivity experiments. We found that the Delta tku70 strain showed increased sensitivity to bleomycin, which induces DNA double-strand breaks, and that the Delta dmm2 strain was sensitive to bleomycin, camptothecin (an inhibitor of type I topoisomerases), and hydroxyurea (a deoxynucleotide synthesis inhibitor). The double-mutant Delta tku70&dmm2 showed higher sensitivity to hydroxyurea, camptothecin, and bleomycin than either of the single mutants. Knockout of dmm2 significantly increased cellulase production. Conclusions Our data show, for the first time, that ferrochelatase encoded by hem8 catalyzes the final step in heme biosynthesis from highly photoreactive porphyrins and that dmm2 encodes a putative DNA methylation modulator-2 protein related to DNA repair and cellulase expression in T. reesei. Our data provide important insights into the roles of this three-gene cluster in T. reesei and other Sordariomycetes and show that the DNA methylation modulator DMM2 affects cellulase gene expression in T. reesei.