BACKGROUND: Transcription activator-like effector nucleases (TALENs) have 
emerged as a tool for enabling targeted gene editing and disruption in difficult 
systems, such as human pluripotent stem cells (hPSCs). The modular architecture 
of TAL effectors theoretically enables targeting of any genomic locus and 
several cloning systems for custom TALEN assembly have recently been 
established. However, there is a lack of versatile TALEN expression systems 
applicable to hPSCs.
RESULTS: Here, we extend an existing TALE assembly system by a dual set of 
expression vectors for efficient application of TALEN technology in hPSCs. This 
is characterized by improved TALEN architecture as well as antibiotic resistance 
and fluorescent reporter cassettes, thus enabling enrichment for transfected 
cells. Improved functionality of the combined system was demonstrated by 
targeted disruption of the HPRT1 gene to create isogenic disease models of 
Lesch-Nyhan-Syndrome. Using female hPSCs, homozygous disruption of HPRT1 
occurred at efficiencies of up to 15%. Differentiating isogenic knock-out cells 
both into central nervous system (CNS) as well as into sensory-like neurons 
recapitulated previously described phenotypes based on patient-specific induced 
PSCs and extended these findings to non-CNS neurons, respectively.
CONCLUSION: The combined vector system allows for flexible and affordable 
generation of knock-out hPSCs lines, thus enabling investigation of 
developmental processes as well as the generation of isogenic disease models 
without the need for patient material.