Biology subjects

Oh, S. Y.

Publications and source records attributed to Oh, S. Y..

3 recordsLinked to original sources

bioRxiv2017

Reducing resistance allele formation in CRISPR gene drives

CRISPR gene drives can efficiently convert heterozygous cells with one copy of the drive allele into homozygotes, thereby enabling super-Mendelian inheritance. This mechanism could be used, for example, to rapidly disseminate a genetic payload through a population, promising novel strategies for the control of vector-borne diseases. However, all CRISPR gene drives tested have produced significant quantities of resistance alleles that cannot be converted to drive alleles and would likely prevent these drives from spreading in a natural population. In this study, we assessed three strategies for reducing resistance allele formation. First, we directly compared drives with the nanos and vasa promoters, which showed that the vasa drive produced high levels of resistance alleles in somatic cells. This was not observed in the nanos drive. Another strategy was the addition of a second gRNA to the drive, which both significantly increased the drive conversion efficiency and reduced the formation rate of resistance alleles. Finally, to minimize maternal carryover of Cas9, we assessed the performance of an autosomal drive acting in the male germline, and found no subsequent formation of resistance alleles in embryos. Our results mark a step toward developing effective gene drives capable of functioning in natural populations and provide several possible avenues for further reduction of resistance rates.

genetics↗

bioRxiv2017

Novel CRISPR/Cas9 gene drive constructs in Drosophila reveal insights into mechanisms of resistance allele formation and drive efficiency in genetically diverse populations

A functioning gene drive system could fundamentally change our strategies for the control of vector-borne diseases by facilitating rapid dissemination of transgenes that prevent pathogen transmission or reduce vector capacity. CRISPR/Cas9 gene drive promises such a mechanism, which works by converting cells that are heterozygous for the drive construct into homozygotes, thereby enabling super-Mendelian inheritance. Though CRISPR gene drive activity has already been demonstrated, a key obstacle for current systems is their propensity to generate resistance alleles. In this study, we developed two CRISPR gene drive constructs based on the nanos and vasa promoters that allowed us to illuminate the different mechanisms by which resistance alleles are formed in the model organism Drosophila melanogaster. We observed resistance allele formation at high rates both prior to fertilization in the germline and post-fertilization in the embryo due to maternally deposited Cas9. Assessment of drive activity in genetically diverse backgrounds further revealed substantial differences in conversion efficiency and resistance rates. Our results demonstrate that the evolution of resistance will likely impose a severe limitation to the effectiveness of current CRISPR gene drive approaches, especially when applied to diverse natural populations.

genetics↗

bioRxiv2016

PRDX6 inhibits neurogenesis of neural precursor cells through downregulation of wdfy1 mediated TLR4 signal

Impaired neurogenesis has been associated with brain disorders. The role of peroxiredoxin 6 (PRDX6) in the neurodegenerative diseases is very controversial. To demonstrate the role of PRDX6 in neurogenesis, we compared neurogenesis ability and studied the molecular mechanisms. It was found that the neurogenesis of neural stem cells and expression of the marker protein were lowered in PRDX6 Tg-mice compared with non-tg mice. Moreover, the expression of wdfy1 was dramatically decreased in PRDX6-Tg mice, also, we observed that wdfy1 siRNA decreases the differentiation ability of primary neural stem cells to astrocyte and neuronal cells as well as PC12 cells. However, knockdown of PRDX6 recovered neurogenesis in the brain of PRDX6-Tg mice as well as PC-12 cells. We also showed that TLR4 was dramatically reduced in PRDX6 Tg mice as well as PC-12 cells and PRDX6 overexpression reduced neurogenesis was rescued after treatment of TLR4 siRNA. We further found that reduced TLR4 expression and neurogenesis was reversed in the neuron from PRDX6-Tg mice as well as PC12 cells by introduction of wdfy1 plasmid. Moreover, TLR4 siRNA reduced neurogenesis and wdfy1 expression. This study indicated that PRDX6 inhibits neurogenesis of neural precursor cells through TLR4 dependent downregulation of wdfy1.

developmental biology↗