Alan Y. Sakaguchi, Ph.D.Associate Professor
University of Southern California, 1978
Dr. Sakaguchi is a lecturer and laboratory instructor in Gross Anatomy and Embryology for 1st year medical students and in Gross Anatomy for the Occupational Therapy program. He directs the section on In vitro Cell Growth and Transfection for Core Course IV: Methods in Cell Biology. Dr. Sakaguchi currently serves on the Preclinical Promotions Committee in the School of Medicine.
My research interests include the role of telomeres in genome stability, cell growth regulation, oncogenesis, and human disease. Telomeres protect chromosome termini and prevent chromosome rearrangements, end-to-end fusion and illegitimate recombination. The shortening of telomeres during replication of most normal somatic cells may function as a tumor suppressor mechanism that prevents the immortalization step in carcinogenesis, and might also contribute to human diseases such as Werner syndrome, ataxia telangiectasia, and dyskeratosis congenita. We are interested in the roles of telomere binding proteins in telomere metabolism and chromosome stability. Our research focuses on mammalian TRF1 and TRF2 proteins that bind the double-stranded vertebrate telomere repeat (TTAGGG) and the KU70 protein which has a dual role in DNA repair and telomere stability. TRF1 can regulate telomere length through poorly understood mechanisms whereas TRF2 prevents end-to-end telomere fusions which may result from attrition of telomeric DNA.
We have identified new cDNA isoforms of human and mouse TRF proteins and are testing the hypothesis that they carry out distinct functions in telomere regulation, perhaps via an altered interaction with other telomere-associated proteins such as KU70. We employ RNA-ligation mediated RACE to isolation new TRF isoforms, and epitope tagging with green fluorescent protein to track the locations of isoforms in cells. We are also testing the hypothesis that TRF2 protein, which is over-expressed in over 2/3 of human breast carcinomas, may promote carcinogenesis in this human disease.
In vitro mutagenesis
Sakaguchi, A. Y., S. S. Padalecki, V. Mattern, A. Rodriguez, R. J. Leach, J. R. McGill, M. Chavez, and T. A. Giambernardi. (1998) Chromosomal localization of the transcribed human telomere repeat binding factor 2 gene and comparative mapping in the mouse. Somat. Cell and Molec. Genet. 24:157-163.
Young, A. C., M. Chavez, T. A. Giambernardi, V. Mattern, J. R. McGill, J. M. Harris, M. F. Sarosdy, P. Patel, and A. Y. Sakaguchi. (1997) Organization and expression of human telomere repeat binding factor genes. Somat. Cell and Molec. Genet. 23:275-286.
Sakaguchi, A. Y., M. Sedlak, V. Rogeness, J. M. Harris, and M. F. Sarosdy. (1996) Determining exon-intron junctions using uncloned genomic walking libraries and direct P1 sequencing. Genetics (Life Sci. Adv.)14:19-25.
Sakaguchi, A. Y. (1996) Cautionary note on the use of dUMP-containing PCR primers with Pfu and VentR DNA polymerases. BioTechniques 21:368-370.