Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator
Abstract Background The filamentous fungus Trichoderma reesei (T. reesei) is a natural producer of cellulolytic and xylanolytic enzymes and is therefore industrially used. Many industries require high amounts of enzymes, in particular cellulases. Strain improvement strategies by random mutagenesis y...
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| Format: | Article |
| Language: | English |
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BMC
2018-08-01
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| Series: | Fungal Biology and Biotechnology |
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| Online Access: | http://link.springer.com/article/10.1186/s40694-018-0059-0 |
| _version_ | 1828938410931257344 |
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| author | Alice Rassinger Agnieszka Gacek-Matthews Joseph Strauss Robert L. Mach Astrid R. Mach-Aigner |
| author_facet | Alice Rassinger Agnieszka Gacek-Matthews Joseph Strauss Robert L. Mach Astrid R. Mach-Aigner |
| author_sort | Alice Rassinger |
| collection | DOAJ |
| description | Abstract Background The filamentous fungus Trichoderma reesei (T. reesei) is a natural producer of cellulolytic and xylanolytic enzymes and is therefore industrially used. Many industries require high amounts of enzymes, in particular cellulases. Strain improvement strategies by random mutagenesis yielded the industrial ancestor strain Rut-C30. A key property of Rut-C30 is the partial release from carbon catabolite repression caused by a truncation of the repressor Cre1 (Cre1-96). In the T. reesei wild-type strain a full cre1 deletion leads to pleiotropic effects and strong growth impairment, while the truncated cre1-96 enhances cellulolytic activity without the effect of growth deficiencies. However, it is still unclear which function Cre1-96 has in Rut-C30. Results In this study, we deleted and constitutively expressed cre1-96 in Rut-C30. We found that the presence of Cre1-96 in Rut-C30 is crucial for its cellulolytic and xylanolytic performance under inducing conditions. In the case of the constitutively expressed Cre1-96, the cellulase activity could further be improved approximately twofold. The deletion of cre1-96 led to growth deficiencies and morphological abnormalities. An in silico domain prediction revealed that Cre1-96 has all necessary properties that a classic transactivator needs. Consequently, we investigated the cellular localization of Cre1-96 by fluorescence microscopy using an eYFP-tag. Cre1-96 is localized in the fungal nuclei under both, inducing and repressing conditions. Furthermore, chromatin immunoprecipitation revealed an enrichment of Cre1-96 in the upstream regulatory region of the main transactivator of cellulases and xylanases, Xyr1. Interestingly, transcript levels of cre1-96 show the same patterns as the ones of xyr1 under inducing conditions. Conclusions The findings suggest that the truncation turns Cre1 into an activating regulator, which primarily exerts its role by approaching the upstream regulatory region of xyr1. The conversion of repressor proteins to potential activators in other biotechnologically used filamentous fungi can be applied to increase their enzyme production capacities. |
| first_indexed | 2024-12-14T02:42:08Z |
| format | Article |
| id | doaj.art-15152f3e06ff4b78b194424d98f2b732 |
| institution | Directory Open Access Journal |
| issn | 2054-3085 |
| language | English |
| last_indexed | 2024-12-14T02:42:08Z |
| publishDate | 2018-08-01 |
| publisher | BMC |
| record_format | Article |
| series | Fungal Biology and Biotechnology |
| spelling | doaj.art-15152f3e06ff4b78b194424d98f2b7322022-12-21T23:19:59ZengBMCFungal Biology and Biotechnology2054-30852018-08-015111810.1186/s40694-018-0059-0Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activatorAlice Rassinger0Agnieszka Gacek-Matthews1Joseph Strauss2Robert L. Mach3Astrid R. Mach-Aigner4Institute of Chemical, Environmental and Bioscience Engineering, TU WienFungal Genetics and Genomics Lab, Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life SciencesFungal Genetics and Genomics Lab, Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life SciencesInstitute of Chemical, Environmental and Bioscience Engineering, TU WienInstitute of Chemical, Environmental and Bioscience Engineering, TU WienAbstract Background The filamentous fungus Trichoderma reesei (T. reesei) is a natural producer of cellulolytic and xylanolytic enzymes and is therefore industrially used. Many industries require high amounts of enzymes, in particular cellulases. Strain improvement strategies by random mutagenesis yielded the industrial ancestor strain Rut-C30. A key property of Rut-C30 is the partial release from carbon catabolite repression caused by a truncation of the repressor Cre1 (Cre1-96). In the T. reesei wild-type strain a full cre1 deletion leads to pleiotropic effects and strong growth impairment, while the truncated cre1-96 enhances cellulolytic activity without the effect of growth deficiencies. However, it is still unclear which function Cre1-96 has in Rut-C30. Results In this study, we deleted and constitutively expressed cre1-96 in Rut-C30. We found that the presence of Cre1-96 in Rut-C30 is crucial for its cellulolytic and xylanolytic performance under inducing conditions. In the case of the constitutively expressed Cre1-96, the cellulase activity could further be improved approximately twofold. The deletion of cre1-96 led to growth deficiencies and morphological abnormalities. An in silico domain prediction revealed that Cre1-96 has all necessary properties that a classic transactivator needs. Consequently, we investigated the cellular localization of Cre1-96 by fluorescence microscopy using an eYFP-tag. Cre1-96 is localized in the fungal nuclei under both, inducing and repressing conditions. Furthermore, chromatin immunoprecipitation revealed an enrichment of Cre1-96 in the upstream regulatory region of the main transactivator of cellulases and xylanases, Xyr1. Interestingly, transcript levels of cre1-96 show the same patterns as the ones of xyr1 under inducing conditions. Conclusions The findings suggest that the truncation turns Cre1 into an activating regulator, which primarily exerts its role by approaching the upstream regulatory region of xyr1. The conversion of repressor proteins to potential activators in other biotechnologically used filamentous fungi can be applied to increase their enzyme production capacities.http://link.springer.com/article/10.1186/s40694-018-0059-0Carbon catabolite repressionTrichoderma reeseiCre1Gene regulationTranscription factorCellulases |
| spellingShingle | Alice Rassinger Agnieszka Gacek-Matthews Joseph Strauss Robert L. Mach Astrid R. Mach-Aigner Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator Fungal Biology and Biotechnology Carbon catabolite repression Trichoderma reesei Cre1 Gene regulation Transcription factor Cellulases |
| title | Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator |
| title_full | Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator |
| title_fullStr | Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator |
| title_full_unstemmed | Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator |
| title_short | Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator |
| title_sort | truncation of the transcriptional repressor protein cre1 in trichoderma reesei rut c30 turns it into an activator |
| topic | Carbon catabolite repression Trichoderma reesei Cre1 Gene regulation Transcription factor Cellulases |
| url | http://link.springer.com/article/10.1186/s40694-018-0059-0 |
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