| Telomeres, located at the ends of eukaryotic chromosomes, play a critical role in protecting chromosome integrity and provide a means to overcome the "end replication problem." Telomerase is a ribonucleoprotein reverse transcriptase having the fundamental role of adding terminal telomeric repeats during DNA replication to maintain telomere length. Telomerase reverse transcriptase (TERT) and telomerase RNA (TR) are essential components of the telomerase ribonucleoprotein complex. The regulation of cellular telomere-telomerase pathway is involved in multiple aspects of biology, such as animal aging, cancer, and stem cell behavior. This dissertation describes research in chicken telomere biology, focusing on the characterization of chicken TERT (cTERT) alternative splicing variation and the expression of cTERT variants in chicken cells in vivo and in vitro. Chapter One is a literature review. Chapter Two describes the characterization of the karyotype stability and chromosomal aberrations in an important chicken cell line DT40. Chapter Three includes an initial study of cTERT alternative variants and their expression in a wide range of chicken cell types. Chapter Four describes the quantitative transcript profiles of cTERT variants as well as chicken TR (cTR) in cells positive and negative for telomerase activity. Chapter Five includes a study on down-regulation of cTERT variant 4 transcript level by RNA interference in DT40 cells. These results provide baseline information for further study of cTERT alternative splicing and cTR functions in an important vertebrate model system. |
