Widespread discrepancy in Nnt genotypes and genetic backgrounds complicates granzyme A and other knockout mouse studies

eLife

Phillip I Bird¹  Thuy T Le²  Kexin Yan²  Daniel J Rawle²  Troy Dumenil²  Cameron Bishop²  Andreas Suhrbier³  Eri Nakayama⁴ 

[1] Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia;QIMR Berghofer Medical Research Institute, Brisbane, Australia;QIMR Berghofer Medical Research Institute, Brisbane, Australia;Australian Infectious Disease Research Centre, GVN Center of Excellence, Brisbane, Australia;QIMR Berghofer Medical Research Institute, Brisbane, Australia;Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan;

关键词: granzyme A;    nicotinamide nucleotide transhydrogenase;    chikungunya;    inflammation;    C57BL/6J;    C57BL/6N;    Mouse;    Viruses;   

DOI  :  10.7554/eLife.70207

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Granzyme A (GZMA) is a serine protease secreted by cytotoxic lymphocytes, with Gzma-/- mouse studies having informed our understanding of GZMA’s physiological function. We show herein that Gzma-/- mice have a mixed C57BL/6J and C57BL/6N genetic background and retain the full-length nicotinamide nucleotide transhydrogenase (Nnt) gene, whereas Nnt is truncated in C57BL/6J mice. Chikungunya viral arthritis was substantially ameliorated in Gzma-/- mice; however, the presence of Nnt and the C57BL/6N background, rather than loss of GZMA expression, was responsible for this phenotype. A new CRISPR active site mutant C57BL/6J GzmaS211A mouse provided the first insights into GZMA’s bioactivity free of background issues, with circulating proteolytically active GZMA promoting immune-stimulating and pro-inflammatory signatures. Remarkably, k-mer mining of the Sequence Read Archive illustrated that ≈27% of Run Accessions and ≈38% of BioProjects listing C57BL/6J as the mouse strain had Nnt sequencing reads inconsistent with a C57BL/6J genetic background. Nnt and C57BL/6N background issues have clearly complicated our understanding of GZMA and may similarly have influenced studies across a broad range of fields.

【 授权许可】

CC BY