C57BL/6NCrl-Adslem1(Y114H)Ccpcz

Gene SymbolAdsl
Gene NameAdenylosuccinate Lyase
Gene Synonym(s)/
ENSEMBLhuman: ENSG00000239900
mouse: ENSMUSG00000022407
Allele SymbolC57BL/6NCrl-Adslem1(Y114H)Ccpcz
Allele Nameendonuclease-mediated allele 1, Ccpcz
Allele Typepoint mutation, Y114H
Genomic locationhuman:  Chromosome 22: 40,346,461-40,390,463 forward strand, GRCh38:CM000684.2
mouse:  Chromosome 15: 80,832,691-80,855,147 forward strand, GRCm39:CM001008.3
Strain of OriginC57Bl/6NCrl
Molecular NoteMutation introduced by CRISPR/Cas9 double strand break and electroporation of dsDNA template with >40 bp homologous arms. Genotyped by PCR amplification of the sequence surrounding the mutation site and subsequent restriction digest by BmgBI as well as Sanger sequencing.
Mutations Made byCzech Centre of Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences

Description

Adenylosuccinate lyase (adenylosuccinase, ADSL; EC 4.3.2.2) is an enzyme involved in 2 pathways of purine nucleotide metabolism. It catalyzes cleavage of succinyl groups to yield fumarate: the conversion of succinylaminoimidazole carboxamide ribotide (SAICAR) into aminoimidazole carboxamide ribotide (AICAR) along the de novo pathway, and the formation of adenylate (AMP) from adenylosuccinate (S-AMP) in the conversion of inosine monophosphate (IMP) into adenine nucleotides in the purine nucleotide cycle (summary by Jurecka et al., 2008).

Associated pathology

ADENYLOSUCCINATE DEFICIENCY (ADSL)

ADSL, various described mutations (P75A, Y114H, R190Q, M225T, K246E, D397Y, S413P, R426H)

Adenylosuccinase deficiency is an autosomal recessive inborn error of metabolism caused by an enzymatic defect in de novo purine synthesis (DNPS) pathway. ADSL deficiency leads to the accumulation of toxic intermediates, including succinyladenosine (S-Ado) and succinylaminoimidazole carboxamide riboside (SAICAr) in body fluids. There are 3 major phenotypic forms of the disorder that correlate with different values of the S-Ado and SAICAr concentration ratios (S‑Ado/SAICAr) in the cerebrospinal fluid. These include the most severe fatal neonatal encephalopathy (S-Ado/SAICAr ratio less than 1); childhood form (type I) with severe psychomotor retardation (S-Ado/SAICAr ratio close to 1), and a milder form (type II) with psychomotor retardation or hypotonia (S-Ado/SAICAr ratio greater than 2) (summary by Baresova et al., 2012).

Model Development

We used a synthetic ssODN carrying the target Y114H mutation plus one extra silent mutation (TAT>CAC) to create a restriction site for BmgBI. ssODN had homologous regions on both sides of the mutation >40 bp long. Used ssODN was premixed with Cas9 protein and gRNA and electroporated into zygotes. Zygotes or 2-cell stage embryos were transferred into pseudopregnant recipient mice. Resulting mice (G0 generation) were genotyped by PCR and subsequent restriction digest. The presence of target Y114H mutation and one extra silent mutation, and no other mutations in the vicinity of targeted region, were confirmed by Sanger sequencing. Positive individuals were backcrossed with C57BL/6NCrl for two generations to establish the colony.