Characterization of HAX1 a long ncRNA in Trichoderma reesei

Recently, the spectrum of classical functions of so-called non-coding RNAs (ncRNAs) has been extended to additional aspects in cell biology. This is in particular due to intense investigations on this topic in the field of molecular biology applied in human medical research. In addition to classical gene regulation by transcription factors, a number of different ncRNA groups are nowadays seen as key regulatory factors in cells, drawing a bow from their involvement in embryonic development to tumor genesis. Although there are good indications for their existence in eukaryotes like filamentous fungi, only negligible research is carried out in biotechnological relevant microorganisms and no corresponding applications for e.g. industrially used fungi have been reported up to now. In this project the long ncRNA HAX1, that is the hypothetical activator of Xyr1 (Xylanase regulator 1), which was recently isolated and preliminarily characterized by the team of the project initiator, is the main objective of research. Its structure, its molecular mechanistic mode of action, and its regulatory impact on gene expression will be determined. In particular, the involvement of HAX1 in plant cell wall degrading enzyme production in Trichoderma reesei will be investigated. Obtained results are expected to provide novel insights in fundamental regulatory circuits of gene expression in lower eukaryotes on the one hand and to reveal a new manipulation level of for targeted strain improvement of industrially important filamentous fungi on the other hand.

Recently, the spectrum of functions of non-coding ribonucleic acids (ncRNAs) has been extended to a number of aspects in cell biology. This is - amongst others - in particular due to intense investigations in the field of molecular biology for human medical research. In addition to classical gene regulation by transcription factors, a number of different ncRNA groups are nowadays seen as key regulatory elements in cells drawing a bow from their involvement in embryonic development to tumor genesis. Among others, filamentous fungi such as Aspergillus, Trichoderma and Penicillium have great biotechnological relevance in the production of organic acids, enzymes and antibiotics. Although there is good evidence for the existence of ncRNAs in lower eukaryotes such as these fungi, little research was done in biotechnologically relevant microorganisms, nor are reports of any applications available. During this project, the long ncRNA HAX1, discovered in the team of the project initiator, was the central research topic. Its structure, its molecular mechanistic mode of action and its function in the regulation of gene expression were studied. In particular, the involvement of HAX1 in the expression and production of plant cell wall-degrading enzymes by the fungus Trichoderma reesei, which is the world`s most prominent biotechnological producer of these enzymes, was investigated. These enzymes have a wide range of applications ranging from the food and feed, the paper and textile industry to biofuel production. The obtained results led to a deeper insight into the regulatory relationships of gene expression involving the action of this long ncRNA. It is particularly noteworthy that this epigenetic phenomenon undergoes a change in the industrial production strains. Structure and length of HAX1 seem to evolve with increasing enzyme production. If a HAX1 version of a production strain is transferred to the wild-type strain, it also shows a considerably increased enzyme production. This during the project developed tool, completely new in biotechnology, was patented by the world`s largest enzyme producer and served as an essential basis for the establishment of a Christian Doppler Laboratory with this industry partner. In the future, tailor-made variants of HAX1 will be used to change the epigenetic landscape of industrial strains and thereby significantly increasing their productivity and stability.