Exploring interactions between Epstein-Barr virus transcription factor Zta and the human genome

Naranjo Perez Fernandez, Ijiel Barak (2018) Exploring interactions between Epstein-Barr virus transcription factor Zta and the human genome. Doctoral thesis (PhD), University of Sussex.

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Abstract

Epstein-Barr virus is a gamma herpesvirus that is present in human adult’s B-lymphocytes infecting 90% of the global population. EBV causes many types of lymphoma and carcinoma. The virus life cycle can be divided in two stages, latency and lytic cycle. Viral gene BZLF1 codes for the viral transcription and replication factor Zta (also known as BZLF1, ZEBRA, EB1, and Z) which is part of the signalling required to switch from latency to the lytic cycle. Zta is part of the bZIP family of proteins, it forms homodimers and can bind to specific sequences termed Zta Response Elements (ZREs). It binds to the EBV lytic origin of replication as well as to specific targeted promoters in the viral genome and regulates its expression. Recent research found and mapped interactions between the key viral transcription factor Zta and the B-cell genome, this showed interactions of Zta proximal (closer than 2Kb) and distal (farther than 2 Kb) to the transcription start site of several genes.

In this work, I asked the questions: Can enhancer properties be found in the sequences where Zta binds to? Is Zta distally regulating expression by looping of DNA? This was approached first by identifying potential sequences that could be conferring enhancing activity, then inserting them into vectors and transfecting them into two different cell lines. In this way, through luciferase reporter assays, any enhancing capabilities of the sequences were tested when placed in a proximal and distal manner to promoters known to be regulated by Zta, as well as mutated promoters not regulated by Zta. This resulted in finding discreet enhancer activity in the sequences analysed, with some being specific to the cell type that was used in the experiment. To answer the second question, chromosome conformation capture (3C) was used to test the possibility of a spatial rearrangement bringing together distal Zta binding regions and promotor regions of selected genes (looping). However, I did not find evidence of looping between Zta binding sites and the neighbouring promoters analysed, in the cell context employed.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QP Physiology > QP0501 Animal biochemistry > QP0551 Proteins, amino acids, etc. > QP0552 Special proteins (other than amino acids, enzymes, or hormones), A-Z > QP0552.T6 Transcription Factors
R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology Including cancer and carcinogens
Depositing User: Library Cataloguing
Date Deposited: 20 Jun 2018 16:13
Last Modified: 20 Jun 2018 16:20
URI: http://sro.sussex.ac.uk/id/eprint/76667

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