System Biosciences View Institution's Website 2 articles published in JoVE Genetics CRISPR-Mediated Reorganization of Chromatin Loop Structure Stefanie L. Morgan*1,2, Erin Y. Chang*1, Natasha C. Mariano1, Abel Bermudez3, Nicole L. Arruda4, Fanting Wu5, Yunhai Luo1, Gautam Shankar1, Star K. Huynh1, Chiao-Chain Huang5, Sharon J. Pitteri3, Kevin C. Wang1,2,6 1Department of Dermatology, Program in Epithelial Biology, Stanford University School of Medicine, 2Program in Cancer Biology, Stanford University School of Medicine, 3Canary Center for Cancer Early Detection, Department of Radiology, Stanford University School of Medicine, 4Department of Biology, Bridgewater State University, 5System Biosciences, 6Veterans Affairs Healthcare System Chromatin looping plays a significant role in gene regulation; however, there have been no technological advances that allow for selective and reversible modification of chromatin loops. Here we describe a powerful system for chromatin loop re-organization using CRISPR-dCas9 (CLOuD9), demonstrated to selectively and reversibly modulate gene expression at targeted loci. Immunology and Infection Packaging HIV- or FIV-based Lentivector Expression Constructs & Transduction of VSV-G Pseudotyped Viral Particles Amy Mendenhall1, Jacob Lesnik1, Chandreyee Mukherjee1, Travis Antes1, Ranjita Sengupta1 1System Biosciences Lentiviral expression vectors are the most effective vehicles for stably expressing different effector molecules or reporter constructs in dividing and non-dividing mammalian cells and whole organisms. Here we provide a protocol on how to package lentivector expression constructs in pseudoviral particles and to transduce target cells using the pseudoviral particles.