Genome editing with the CRISPR Cas9 system

Genome engineering is just about its dawn of golden age. New and exciting tools are arising and piling up to its arsenal. After TALENs and Zing-finger a new and lot worthy tool is coming to add up. The newest addition is the CRISPR system. A system that firstly discovered at the Streptococcus thermophilus and its natural role is the sequence-specific adaptive immunity against foreign DNA in bacteria. In the present report, CRISPR Cas9, type II system, is used in an attempt to knock out the HPRT1 gene expressed in lymphocytes as a proof of concept. HAT medium in combination with Thioguanine is used as a selection medium enabling a quick and simple read-out screening method. To verify that a successful editing event took place in the mammalian cells, a detection DNA cleavage kit is used in combination with an enzymatic assay.