Introduction of pathogenic mutations into the mouse Psen1 gene by Base Editor and Target-AID
NATURE COMMUNICATIONS
Authors: Sasaguri, Hiroki; Nagata, Kenichi; Sekiguchi, Misaki; Fujioka, Ryo; Matsuba, Yukio; Hashimoto, Shoko; Sato, Kaori; Kurup, Deepika; Yokota, Takanori; Saido, Takaomi C.
Abstract
Base Editor (BE) and Target-AID (activation-induced cytidine deaminase) are engineered genome-editing proteins composed of Cas9 and cytidine deaminases. These base-editing tools convert C:G base pairs to T:A at target sites. Here, we inject either BE or Target-AID mRNA together with identical single-guide RNAs (sgRNAs) into mouse zygotes, and compare the base-editing efficiencies of the two distinct tools in vivo. BE consistently show higher base-editing efficiency (10.0-62.8%) compared to that of Target-AID (3.4-29.8%). However, unexpected base substitutions and insertion/deletion formations are also more frequently observed in BE-injected mice or zygotes. We are able to generate multiple mouse lines harboring point mutations in the mouse presenilin 1 (Psen1) gene by injection of BE or Target-AID. These results demonstrate that BE and Target-AID are highly useful tools to generate mice harboring pathogenic point mutations and to analyze the functional consequences of the mutations in vivo.
Next-generation sequencing reveals substantial genetic contribution to dementia with Lewy bodies
NEUROBIOLOGY OF DISEASE
Authors: Geiger, Joshua T.; Ding, Jinhui; Crain, Barbara; Pletnikova, Olga; Letson, Christopher; Dawson, Ted M.; Rosenthal, Liana S.; Pantelyat, Alexander; Gibbs, J. Raphael; Albert, Marilyn S.; Hernandez, Dena G.; Hillis, Argye E.; Stone, David J.; Singleton, Andrew B.; Hardy, John A.; Troncoso, Juan C.; Scholz, Sonja W.
Abstract
Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia after Alzheimer's disease. Although an increasing number of genetic factors have been connected to this debilitating condition, the proportion of cases that can be attributed to distinct genetic defects is unknown. To provide a comprehensive analysis of the frequency and spectrum of pathogenic missense mutations and coding risk variants in nine genes previously implicated in DLB, we performed exome sequencing in 111 pathologically confirmed DLB patients. All patients were Caucasian individuals from North America. Allele frequencies of identified missense mutations were compared to 222 control exomes. Remarkably, similar to 25% of cases were found to carry a pathogenic mutation or risk variant in APP, GBA or PSEN1, highlighting that genetic defects play a central role in the pathogenesis of this common neurodegenerative disorder. In total, 13% of our cohort carried a pathogenic mutation in GBA, 10% of cases carried a risk variant or mutation in PSEN1, and 2% were found to carry an APP mutation. The APOE 64 risk allele was significantly overrepresented in DLB patients (p-value <0.001). Our results conclusively show that mutations in GBA, PSEN1, and APP are common in DLB and consideration should be given to offer genetic testing to patients diagnosed with Lewy body dementia. Published by Elsevier Inc.