John Wilson, Ph.D.
Professor, Biochemistry and Molecular Biology, Molecular and Human Genetics
Baylor College of Medicine
A.B., Chemistry/Biology, Wabash College(1966)
Ph.D., Biochemistry/Genetics, Caltech(1971)
Biochemistry, Stanford University(1971-73)
Dr. Wilson's laboratory is interested in two, complementary aspects of genome biology in mammalian cells: defining the pathways that normally guarantee genome integrity, and manipulating those pathways to accomplish precise modifications for gene therapy. They are exploring these interests in the context of two inherited human neurological diseases: myotonic dystrophy and retinitis pigmentosa.
Myotonic dystrophy (DM) is one of a growing number of human neurological diseases that are caused by the intergenerational expansion of trinucleotide (triplet) repeats. Like other repeats, the CTG/CAG triplet repeat responsible for DM is unstable because it tends to form secondary structures —hairpins and slipped-strand structures —that interfere with DNA metabolism, leading to repeat expansion and disease. They have developed exquisitely sensitive assays that use the selectable APRT and HPRT genes to detect repeat instability in mammalian cells. These assays reveal that CTG/CAG triplet repeats are only mildly destabilized by replication —the principal cause of instability in bacteria and yeast —but are dramatically destabilized by transcription through the repeat and by genome-wide demethylation. Notably, in human patients triplet repeats are extremely unstable during gametogenesis and early embryogenesis, precisely those times when the genome in undergoing substantial changes in DNA methylation. Also, triplet repeats are commonly unstable in non-dividing cells, where transcription —but not replication —might play a key role. The Wilson Lab is exploring the pathways for transcription-induced and demethylation-induced instability using RNAi technology in cells and genetic approaches in mice.
Retinitis pigmentosa (RP), which affects 1/3000 people worldwide, begins with loss of peripheral vision in the teens and progresses over the next 30 years, or so, to tunnel vision and blindness. They are developing gene-specific strategies for genome modification, with the ultimate aim of treating this disease in humans. Dominant mutations in the rhodopsin gene, which encodes the photopigment in rod photoreceptors, are the largest single cause of RP. To develop treatment protocols, they initially constructed a mouse model by replacing the mouse rhodopsin gene with the human gene fused to GFP. Human rhodopsin-GFP is expressed normally in mouse rod cells and provides a convenient color marker for ready assessment of treatment efficacy. They have now generated additional mouse lines, each of which carries a mutant human rhodopsin-GFP gene that prevents expression of GFP, allowing them to detect gene correction by the appearance of green fluorescence in an otherwise black retina. Using such modified animals, they have recently demonstrated that we can efficiently introduce double-strand breaks into the rhodopsin gene in rod cells in mice. These breaks can be repaired by both homologous recombination (HR) and nonhomologous end joining (NHEJ), demonstrating for the first time that these DNA repair process operate effectively in terminally differentiated rod cell neurons.
- Lin WY, Wilson JH and Lin Y. Repair of chromosomal double-strand breaks by precise ligation in human cells. DNA Repair (Amst), 12(7):480-7 (2013). PubMed
- Price BA, Sandoval IM, Chan F, Nichols R, Roman-Sanchez R, Wensel TG and Wilson JH. Rhodipsin gene expression determines rod outer segment size and rod cell resistance to a dominant-negative neurodegeneration mutant. PLoS One, 7(11):e49889 (2012). PubMed
- Lin Y and Wilson JH. Nucleotide excision repair, mismatch repair, and R-loops modulate convergent transcription-induced cell death and repeat instability. PLoS One, 7(10):e46807 (2012). PubMed
- Price BA, Sandoval IM, Chan F, Simons DL, Wu SM, Wensel TG and Wilson JH. Mislocalization and degradation of human P23H-rhodopsin-GFP in a knock-in mouse model of retinitis pigmentosa. Invest Ophthalmol Vis Sci, 52:9728-9736 (2011). PubMed
- Hubert L Jr, Lin Y, Dion V and Wilson JH. Xpa deficiency reduces CAg trinucleotide repeat instability in neuronal tissues in a CA1 mouse model. Hum Mol Genet, 20:4822-4830 (2011). PubMed
- Chan F, Hauswirth WW, Wensel TG and Wilson JH. Efficient mutagenesis of the rhodopsin gene in rod photoreceptor neurons in mice. Nucleic Acids Res, 39:5955-5966 (2011). PubMed
- Lin Y and Wilson JH. Transcription-induced DNA toxicity at trinucleotide repeats: Double bubble is trouble. Cell Cycle, 10:611-618 (2011). PubMed
For more publications, see listing on PubMed.
Department: Biochemistry and Molecular Biology
Address: Baylor College of Medicine
One Baylor Plaza
Houston, TX 77030
Additional Links: Biochemistry and Molecular Biology