Locus Control Regions (LCR) are cis-acting gene regulatory elements with the unique, integration site-independent ability to transfer the characteristics of their locus-of-origin’s gene expression pattern to a linked transgene in mice. LCR activities have been discovered in numerous T cell lineage expressed gene loci. These elements can be adapted to the design of stem cell gene therapy vectors that direct robust therapeutic gene expression to the T cell progeny of engineered stem cells. Currently, transgenic mice provide the only experimental approach that wholly supports all the critical aspects of LCR activity. In this talk I will describe our discovery that all key features of mouse T cell receptor (TCR)-α gene LCR function can be manifested in T cells derived in vitro from mouse embryonic stem cells (ESC). High level, copy number-related TCRα LCR-linked reporter gene expression levels are cell type-restricted in this system, and upregulated during the expected stage transition of T cell development. We also confirmed that de novo introduction of TCRα LCR linked transgenes into existing T cell lines yields incomplete LCR activity. Together, these data indicate that establishing full TCRα LCR activity requires critical molecular events occurring prior to final T-lineage determination. This study additionally validates a novel, tractable and more rapid approach for the study of LCR activity in T cells, and its translation to therapeutic genetic engineering. [This work was initiated under NYS-DOH-NYSTEM grant C024302 (B.D.O.) and completed with the support of National Institutes of Health grants SC1-GM095402 (to B.D.O.) and RR003037/MD007599 (to Hunter College)].
Benjamin Ortiz, Ph.D. is Associate Professor of Biology at Hunter College. He pursues research on gene regulation during T cell development, while fostering the professional development of numerous members of Hunter’s diverse and talented student body. His laboratory has trained a diverse array of Hunter College alumni who are now pursuing biomedical research careers across the country. His lab studies a Locus Control Region (LCR), a DNA segment harboring potent gene regulatory activity in the T cells of the immune system. His lab has most recently pioneered the study of LCR activity in T cells derived in vitro from embryonic stem cells. This breakthrough promises to speed the translation of basic research on LCR activity to the design of gene therapy strategies against diseases such as cancer, inherited immunodeficiencies and AIDS.
Dr. Ortiz is a Brooklyn native and product of the NYC public schools. He received his B.A. in Biology at Hunter College. The Minority Access to Research Careers (MARC) program at Hunter supported his first research experience, obtained in the laboratory of Dr. Robert Dottin. He was awarded a Howard Hughes Medical Institute Predoctoral Fellowship, with which he went on to earn his Ph.D. in Immunology from Stanford University working in the laboratory of Dr. Alan Krensky. He then conducted postdoctoral research at the University of California, Berkeley in the laboratory of Dr. Astar Winoto. Dr. Ortiz has been on the Hunter College Faculty since 2000. His research has been awarded several grants including a National Science Foundation (NSF) CAREER award, and SCORE and “R01” grants from the National Institutes of Health (NIH). He was also among the first recipients of individual investigator research grants from the Empire State Stem Cell Research Program (NYSTEM). He has served on grant review panels for the Department of Defense, NSF and NIH.
Photo credit to Judith O'Brien.