Characterizing long non‐coding RNA at the DBF4 gene locus

Abstract

Proper regulation of the cell cycle is essential for genetic stability and function. Mutations resulting in deregulation of the cell cycle are attributable to the development of diseases such as cancer. A large portion of the proteins responsible for regulating the cell cycle are found at DNA replication origins making replication origins an attractive target of research. Our lab has previously characterized a replication origin found in the promoter region of the human DBF4 locus which contains two zones at which two Origin Recognition Complexes bind and initiate replication in opposite directions in a specific manner termed Asymmetrical Bidirectional Replication. Within these same zones, our lab has also discovered the presence of transcription start sites for long non-coding RNA (lncRNA) transcripts. We’ve found that these non-coding transcripts are differentially transcribed from their neighboring genes and are resistant to RNA polymerase I, II and III inhibition. Results from these studies unexpectedly indicate the possibility of the mitochondrial RNA polymerase acting in the nucleus to transcribe the lncRNAs at the DBF4 locus. These transcripts are also cyclically more stably expressed than the DBF4 gene while retaining a relatively short half-life. In an attempt to achieve a broader understanding of the replication process, the work in this thesis presents an effort to characterize and identify these lncRNAs initiating in the DBF4 promoter region and provide new insights into their behavior.