Abstract: The present invention utilizes a Cas9 nickase which nicks a flanking target sequence to a duplicated gene sequence (e.g., a retroviral LTR). This nicking causes a genomic collapse of the sequence between the nick and the LTR, thereby deleting the sequence from the genome. Because the nickase does not introduce mutations at the target site, this method can be repeated maximize the efficiency (e.g., 100% of retroviral genome excision. For example, this method is useful to delete all PERVs within a pig genome intended for human transplantation. Further, such PERV-free cells can then be used to clone PERV-free pigs. Furthermore, this method is useful to remove amplified gene repeats in cancer cells.

Abstract: Multi-modal tumor imaging of neuroblastoma is essential for tumor staging, response evaluation and detection of relapsed diseased. The present invention provides a norepinephine analogue with a near-infrared (near-IR) dye, W765-BG, that efficiently and stably detects neuroblastoma in vivo using near-IR optical imaging. Confocal microscopy and optical imaging of neuroblastoma xenografts shows cell specific uptake and reveals exceptional tumor retention with a high tumor-to-tissue ratio up to 7 days after injection of W765-BG.