DNA repair protein RAD51 enhances the CRISPR/Cas9-mediated knock-in efficiency in brain neurons
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Kurihara, Taiga; Kouyama-Suzuki, Emi; Satoga, Michiru; Li, Xue; Badawi, Moataz; Thiha; Baig, Deeba Noreen; Yanagawa, Toru; Uemura, Takeshi; Mori, Takuma; Tabuchi, Katsuhiko
Abstract
Gene knock-in using the CRISPR/Cas9 system can be achieved in a specific population of neurons in the mouse brain, by using in utero electroporation to introduce DNA fragments into neural progenitor cells. Using this strategy, we previously knocked-in the EGFP coding sequence into the N-terminal region of the beta-actin gene specifically in the pyramidal neurons in layer 2/3 of the somatosensory cortex. However, the knock-in efficiency was less than 2% of the transfected neurons. In this study, we sought to improve the knock-in efficiency using this system. First, we varied the length of the homology arms of the beta-actin donor template DNA, and found that the knock-in efficiency was increased to similar to 14% by extending the length of the 5' and 3' homology arms to 1.6 kb and 2.0 kb, respectively. We then tested the effect of the DNA repair protein RAD51 and the knock-in efficiency was increased up to 2.5-fold when co-transfecting with two different beta-actin and a camk2a targeting EGFP knock-in modules. The RAD51 overexpression did not alter the migration of developing neurons, density or morphology of the dendritic spines compared to those in neurons not transfected with RAD51. RAD51 expression will be useful for increasing the knock-in efficiency in neurons in vivo by CRISPR/Cas9-mediated homology directed repair (HDR). (C) 2020 Elsevier Inc. All rights reserved.
Genetic Variation in the Tau Kinases Pathway May Modify the Risk and Age at Onset of Alzheimer's Disease
JOURNAL OF ALZHEIMERS DISEASE
Authors: Luis Vazquez-Higuera, Jose; Mateo, Ignacio; Sanchez-Juan, Pascual; Rodriguez-Rodriguez, Eloy; Pozueta, Ana; Calero, Miguel; Luis Dobato, Jose; Frank-Garcia, Ana; Valdivieso, Fernando; Berciano, Jose; Bullido, Maria J.; Combarros, Onofre
Abstract
Tau abnormal hyperphosphorylation and the formation of neurofibrillary tangles in the Alzheimer's disease (AD) brain is the result of upregulation of tau kinases. In a group of 729 Spanish late-onset AD patients and 670 healthy controls, we examined variations into a set of 20 candidate genes of kinases involved in tau phosphorylation at AD-related sites (PRKACB; CAMK2A; MARK1, 2, 3 and 4; CSNK1D; CDC2; RPS6KB1 and 2; p38 alpha and eta; IB1; JNK1, 2 and 3; MEK1 and 2; ERK1 and 2), to address hypotheses of genetic variation that might influence both AD risk and age at disease onset. There was an increased frequency of RPS6KB2 (intron 2, rs917570) minor allele in patients (50%) versus controls (39%) (OR = 1.52; 95% CI 1.30-1.77; p = 1.24x10(-5) Bonferroni corrected), and the presence of this minor allele was significantly (p = 4.2x10(-5)) associated with a 3-years later onset of AD (mean age 74.1 years) when compared to age at onset of non-minor allele carriers (mean age 71.1 years). In APOE non-epsilon 4 allele carriers, the combined effect of AD-associated risk alleles from the genes of CDC2, RPS6KB1 and 2, p38 alpha, JNK (1, 2 and 3), MEK2, and ERK2 was significantly (p = 0.002) associated with a late-onset (>76 years) of AD. The CDC2 AGC haplotype derived from SNPs in introns 3 (rs2448347), 5 (rs2456772), and 7 (rs1871447) showed a protective effect against AD in APOE non-epsilon 4 allele carriers (permutation p = 1.0x10(-4)) with a frequency of 9% in cases and 15% in controls. Common genetic variation in the tau kinases pathway does underlie individual differences not only in susceptibility to AD but also in disease phenotype (age at disease onset).