Sangamo's Zinc Finger Protein Gene Editor
manofsan 11 Apr 2005
http://www.sangamo.com/index.php
I just want to better understand how this thing works, and what its weaknesses/limitations are.
Their transcription factor is made of 2 main components (domains). The first is the binding/recognition domain, to properly target the right area of the genome. The second is the functional domain, which is basically the gene you're trying to insert (can even be a knocked-out gene, if you're trying to disable rather than enable something). This apparently is how natural transcription factors work.
What worries me is suppose the binding domain makes a mistake? Seems to me that if if you have some unrelated genomic region that matches most of the binding sequence, there's a chance of the binding sequence still attaching to that genomic site. So I'd think you'd really want detailed information on a patient's genomic sequence before you try to alter it.
I'd like to know just how big a sequence can you slap in there? At what point does this method become unreliable?
What are things that help or favor this technique working correctly?
What is the epigenetic impact? From what you've told me, the methylation regulatory stuff only applies to the promoter portion of a gene sequence, so it sounds to me that if you don't mess with the promoter portion, you're not going affect the epigenetic side of things. Correct?
What are the various possible ways in which this thing can go wrong, and cause problems?
manofsan 11 Apr 2005
http://www.nature.co...s=doi1113194443
Darn, I wish I could access the actual article itself (no subscription) :(
11 Apr 2005
TOWARDS SAFE,NON-VIRAL THERAPEUTIC GENE EXPRESSION IN HUMANS
Dominic J.Glover, Hans J.Lipps and David A.Jans
The potential dangers of using viruses to deliver and integrate DNA into host cells in gene therapy have been poignantly highlighted in recent clinical trials. Safer, non-viral gene delivery approaches have been largely ignored in the past because of their inefficient delivery and the resulting transient transgene expression. However, recent advances indicate that efficient, long-term gene expression can be achieved by non-viral means. In particular, integration of DNA can be targeted to specific genomic sites without deleterious consequences and it is possible to maintain transgenes as small episomal plasmids or artificial chromosomes. The application of these approaches to human gene therapy is gradually becoming a reality.