Research – ACS Synthetic Biology – The impact of chromatin dynamics on Cas9-mediated genome editing in human cells
The impact of chromatin dynamics on Cas9-mediated genome editing in human cells
Daer RM, Cutts JP, Brafman DA, Haynes KA (2016) ACS Synthetic Biology. doi: 10.1021/acssynbio.5b00299
We used a chromatin switch system to compare the efficiency of human gene editing (via CRISPR/Cas9) before and after DNA had become packaged with nuclear proteins. The DNA-nuclear protein complex (called chromatin) ‘turns the dials’ of gene expression. Here, we discovered that this dialing mechanism can also disrupt artificial genome editing. We also found that readjusting chromatin could restore gene editing, which has implications for improving CRISPR for use in stem cell genomes, where key genes are often tightly packaged in chromatin.
- Pre-print: The impact of chromatin dynamics on Cas9-mediated genome editing in human cells. Daer RM, Cutts JP, Brafman DA, Haynes KA (2016) bioRxiv. doi: http://dx.doi.org/10.1101/071464
- Just how easy is it to edit DNA? PRI’s Science Friday with Ira Flatow. http://www.sciencefriday.com/segments/just-how-easy-is-it-to-edit-dna/
Research – Nature – Regulation of cancer epigenomes with a histone-binding synthetic transcription factor
Regulation of cancer epigenomes with a histone-binding synthetic transcription factor.
Nyer DB, Daer R, Vargas D, Hom C, Haynes KA. (2017) Nature Genomic Medicine. http://rdcu.be/oqv7
This work expands our 2011 report in many important ways. We studied the behavior of a synthetic chromatin protein that we designed called PcTF in bone, blood, and brain cancer-derived cells. We expected to see PcTF bind to methylated histones, but instead saw strong signals closer to histone-free gene promoters. However, PcTF activity still required the methyl-histone binding domain to interact with its targets. It appears that PcTF bridges methylated histone signals with the transcription complex. We also discovered that PcTF activates a key tumor suppressor, CASZ1 as well as other silenced genes in all three cancer cell types. This new information has advanced our understanding of how a potentially therapeutic histone-binding protein behaves in cancer cells.
- Pre-print: Regulation of cancer epigenomes with a histone-binding synthetic transcription factor. Nyer DB, Vargas D, Hom C, Haynes KA. (2016) bioRxiv. doi: http://dx.doi.org/10.1101/072975
- News: Zrioka P. ASU In The Loop. Karmella Haynes Publishes Paper on Custom-built, Therapeutic Proteins for Cancer Treatment. Link
Research – Biotechnology & Bioengineering – The histone deacetylase inhibitor Entinostat enhances polymer-mediated transgene expression in cancer cell lines
Collaborators from the Haynes Lab (ASU, SBHSE), Rege Lab (ASU, SEMTE), and Elmer Lab (Villanova) published our discovery of how drugs that modify epigenetic mechanisms improve the expression of synthetic genes that are delivered into cultured human cells. Dr. Elmer is the first author. Dr. Haynes and Matt Christensen (Rege Lab) used quantitative PCR to discover that drug treatment led to increased uptake of synthetic DNA into the nuclei of cells. Read the abstract online: http://www.ncbi.nlm.nih.gov/pubmed/26614912.
A sensitive switch for visualizing natural gene silencing in single cells
Haynes KA, Ceroni F, Flicker D, Younger A, Silver PA. (2012) ACS Synth. Biol. 1: 99–106. PMID: 22530199
We designed a synthetic gene switch that expressed cyan fluorescent protein in the presence of microRNAs, which are biomarkers for cell development and disease. The switch was designed to be sensitive to small, hard-to-detect microRNAs in live cells. Here, we demonstrated that the switch responded to natural as well as artificial proof-of-concept microRNA signals.
Synthetic reversal of epigenetic silencing
Haynes KA, Silver PA. (2011) J Biol Chem. 286:27176-82. PMID: 21669865
We developed synthetic gene regulators that interact with epigenetic marks instead of DNA sequences. This research breaks new ground for artificial regulation of genes to stop cancer cell growth. The development of the synthetic chromatin protein marks the beginning of our group’s work in synthetic epigenetics. Cover art was produced by Karmella Haynes.