Identification and analysis of DNA repair mechanisms - Thesis Example

In both of these cases, DNA repair systems involve the use of the Mre11/Rad50/NBS1 complex. This project aims to identify and examine what DNA repair systems are present in the cells of Schizosaccharomyces pombe and how these contribute to resistance to treatment with nucleoside analogues. This information should help to provide further insight into the way in which human cells are able to develop resistance to this form of treatment, and perhaps provide some indication of a method to prevent this.

Table of Contents Abstract 2 Introduction 4 DNA repair and cancer 6 DNA replication 7 DNA repair 9 MRN Complex 11 Topoisomerase inhibitors 13 Nucleoside analogues 15 Involvement of DNA repair 17 Project System 20 Aims and Objectives 21 References 22 Introduction In everyday life, cells are exposed to external and internal agents that cause thousands of DNA mutations per day. These mutations range from being small, such as affecting a single nucleotide, to large mutations where accurate repair can be difficult.

For the accurate propagation of the genetic information within cells, it is essential that the body has mechanisms of repairing damage in a reliable manner. However, while many methods for DNA repair exist, these are not always successful and mutations can accumulate, resulting in the development of cancer (Helleday et al., 2007). Understanding these processes, why they occur the way that they do and what can be done to influence these is crucial for knowing the way that cancer occurs, and determining methods of treating it effectively.

In our modern society, cancer has remained one of the most well studied diseases and perhaps one of the least understood. The fundamental aspects of cancer are damage in the DNA of a cell that results in a lack of control over cell growth and replication, as well reducing the likelihood that cells will enter apoptosis. These cells are able to proliferate well beyond the normal constraints of the tissue that they are in (Loeb and Loeb, 2000). With high levels of replication and low cell death, abnormal cells build up within the body and interfere with body functions.

The exact mechanisms that causes these mutations to occur, and allows the cells to break free of the cell control pathway are the focus of much current research into cancer, as understanding these pathways may help to develop treatment or prevent cells from entering this state. Cancer is a disease where mutations in DNA accumulate to the point that traditional controls over cell behaviour can be bypassed, often involving the accumulation of mutations in genes responsible for the birth or death of the cell, as well as controls over the cell cycle (Lengauer et al., 1998). Research indicates that the tumours developed as the result of cancer are heterogeneous (Loeb et al., 2003). Because of this, cancer needs to be thought of as a collection of disease rather than a single disease (Huang et al., 2006). This is an important factor when studying cancer, as it explains why some mechanisms are prevalent in some forms of cancer, but not others.

Genetic instability is thought to be one of the driving factors of the development of tumours and this in turn is driven by DNA damage and errors in the replication machinery. However, spontaneous mutation is only one aspect of the puzzle, and the prevalence of cancer development and succession of mutations