@phdthesis{Baluapuri2021,
  author    = {Baluapuri, Apoorva},
  title     = {Molecular Mechanisms of MYC's impact on Transcription Elongation},
  doi       = {10.25972/OPUS-24380},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-243806},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Expression of the MYC oncoprotein, which binds the DNA at promoters of most transcribed genes, is controlled by growth factors in non-tumor cells, thus stimulating cell growth and proliferation. Here in this thesis, it is shown that MYC interacts with SPT5, a subunit of the RNA polymerase II (Pol II) elongation factor DSIF. MYC recruits SPT5 to promoters of genes and is required for its association with Pol II. The transfer of SPT5 is mediated by CDK7 activity on TFIIE, which evicts it from Pol II and allows SPT5 to bind Pol II. MYC is required for fast and processive transcription elongation, consistent with known functions of SPT5 in yeast. In addition, MYC increases the directionality of promoters by stimulating sense transcription and by suppressing the synthesis of antisense transcripts. The results presented in this thesis suggest that MYC globally controls the productive assembly of Pol II with general elongation factors to form processive elongation complexes in response to growth-factor stimulation of non-tumour cells. However, MYC is found to be overexpressed in many tumours, and is required for their development and progression. In this thesis it was found that, unexpectedly, such overexpression of MYC does not further enhance transcription but rather brings about squelching of SPT5. This reduces the processivity of Pol II on selected set of genes that are known to be repressed by MYC, leading to a decrease in growth-suppressive gene transcription and uncontrolled tumour growth},
  language  = {en}
}
@phdthesis{Endres2021,
  author    = {Endres, Theresa},
  title     = {PAF1 complex and MYC couple transcription elongation with double-strand break repair},
  doi       = {10.25972/OPUS-24955},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249557},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {The oncogene MYC is deregulated and overexpressed in a high variety of human cancers and is considered an important driver in tumorigenesis. The MYC protein binds to virtually all active promoters of genes which are also bound by the RNA Polymerase II (RNAPII). This results in the assumption that MYC is a transcription factor regulating gene expression. The effects of gene expression are weak and often differ depending on the tumor entities or MYC levels. These observations could argue that the oncogene MYC has additional functions independent of altering gene expression. In relation to this, the high diversity of interaction partners might be important. One of them is the RNAPII associated Factor I complex (PAF1c). In this study, direct interaction between PAF1c and MYC was confirmed in an in-vitro pulldown assay. ChIP sequencing analyses revealed that knockdown of PAF1c components resulted in reduced MYC occupancy at active promoters. Depletion or activation as well as overexpression of MYC led to reduced or enhanced global occupancy of PAF1c in the body of active genes, arguing that MYC and PAF1c bind cooperatively to chromatin. Upon PAF1c knockdown cell proliferation was reduced and additionally resulted in an attenuation of activation or repression of MYC-regulated genes. Interestingly, knockdown of PAF1c components caused an accumulation in S-phase of cells bearing oncogenic MYC levels. Remarkably, enhanced DNA damage, measured by elevated gH2AX and pKAP1 protein levels, was observed in those cells and this DNA damage occurs specifically during DNA synthesis. Strikingly, MYC is involved in double strand break repair in a PAF1c-dependent manner at oncogenic MYC levels. Collectively the data show that the transfer of PAF1c from MYC onto the RNAPII couples the transcriptional elongation with double strand break repair to maintain the genomic integrity in MYC-driven tumor cells.},
  language  = {en}
}
@article{HartmannReisslandMaieretal.2021,
  author    = {Hartmann, Oliver and Reissland, Michaela and Maier, Carina R. and Fischer, Thomas and Prieto-Garcia, Cristian and Baluapuri, Apoorva and Schwarz, Jessica and Schmitz, Werner and Garrido-Rodriguez, Martin and Pahor, Nikolett and Davies, Clare C. and Bassermann, Florian and Orian, Amir and Wolf, Elmar and Schulze, Almut and Calzado, Marco A. and Rosenfeldt, Mathias T. and Diefenbacher, Markus E.},
  title     = {Implementation of CRISPR/Cas9 Genome Editing to Generate Murine Lung Cancer Models That Depict the Mutational Landscape of Human Disease},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {9},
  journal   = {Frontiers in Cell and Developmental Biology},
  issn      = {2296-634X},
  doi       = {10.3389/fcell.2021.641618},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230949},
  year      = {2021},
  abstract  = {Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in both men and women. Despite the development of novel therapeutic interventions, the 5-year survival rate for non-small cell lung cancer (NSCLC) patients remains low, demonstrating the necessity for novel treatments. One strategy to improve translational research is the development of surrogate models reflecting somatic mutations identified in lung cancer patients as these impact treatment responses. With the advent of CRISPR-mediated genome editing, gene deletion as well as site-directed integration of point mutations enabled us to model human malignancies in more detail than ever before. Here, we report that by using CRISPR/Cas9-mediated targeting of Trp53 and KRas, we recapitulated the classic murine NSCLC model Trp53fl/fl:lsl-KRasG12D/wt. Developing tumors were indistinguishable from Trp53fl/fl:lsl-KRasG12D/wt-derived tumors with regard to morphology, marker expression, and transcriptional profiles. We demonstrate the applicability of CRISPR for tumor modeling in vivo and ameliorating the need to use conventional genetically engineered mouse models. Furthermore, tumor onset was not only achieved in constitutive Cas9 expression but also in wild-type animals via infection of lung epithelial cells with two discrete AAVs encoding different parts of the CRISPR machinery. While conventional mouse models require extensive husbandry to integrate new genetic features allowing for gene targeting, basic molecular methods suffice to inflict the desired genetic alterations in vivo. Utilizing the CRISPR toolbox, in vivo cancer research and modeling is rapidly evolving and enables researchers to swiftly develop new, clinically relevant surrogate models for translational research.},
  language  = {en}
}