As a prototype of genomics-guided precision medicine, individualized thiopurine dosing based on pharmacogenetics is a highly effective way to mitigate hematopoietic toxicity of this class of drugs. Recently, NUDT15 deficiency was identified as a genetic cause of thiopurine toxicity, and NUDT15-informed preemptive dose reduction was quickly adopted in clinical settings. To exhaustively identify pharmacogenetic variants in this gene, we developed massively parallel NUDT15 function assays to determine the variants’ effect on protein abundance and thiopurine cytotoxicity. Of the 3,097 possible missense variants, we characterized the abundance of 2,922 variants and found 54 hotspot residues at which variants resulted in complete loss of protein stability. Analyzing 2,935 variants in the thiopurine cytotoxicity-based assay, we identified 17 additional residues where variants altered NUDT15 activity without affecting protein stability. We identified structural elements key to NUDT15 stability and/or catalytical activity with single amino acid resolution. Functional effects for NUDT15 variants accurately predicted toxicity risk alleles in patients treated with thiopurines with far superior sensitivity and specificity compared to bioinformatic prediction algorithms. In conclusion, our massively parallel variant function assays identified 1,152 deleterious NUDT15 variants, providing a comprehensive reference of variant function and vastly improving the ability to implement pharmacogenetics-guided thiopurine treatment individualization.

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CELO virus (fowl adenovirus 1) contained three core polypeptides of molecular weights 20,000, 12,000, and 9,500. The core was similar to that of human adenoviruses, with some evidence of compact subcore domains. Micrococcal nuclease digestion of CELO virus cores produced a smear of DNA fragments of gradually decreasing size, with no nucleosome subunit or repeat pattern. Moreover, when digested cores were analyzed without protease treatment, there was again no evidence of a nucleosome substructure; neither DNA fragments nor core proteins entered a 4% polyacrylamide gel. The organization of the core is thus quite unlike that of chromatin. Restriction endonuclease analysis of the DNA from digested cores showed that the right end was on the outside of the core. We suggest that adenovirus DNA is condensed into the core by cross-linking and neutralization by the core proteins, beginning with the packaging sequence at the center of the core and ending with the right end of the DNA on the outside. Adenoviruses contain an internal core that consists of the viral DNA and the virus-coded, basic core proteins. In human adenovirus, there are two prominent arginine-rich core proteins, the major core protein (polypeptide VII) and the minor core protein (polypeptide V). Of the two, the major core protein is more tightly associated with the viral DNA (4, 14, 15). A third virion polypeptide, designated [i, which is very small and very rich in arginine, may also be associated with the viral DNA (25). The adenovirus terminal protein (43, 44) is covalently linked to the 5' ends of the viral genome. The structure of the adenovirus core has been investigated by electron microscopy, and several different morphological structures have been proposed. Brown et al. (4) proposed that the core was organized into 12 morphological subunits, each under a vertex of the capsid. However, Nermut (38, 39) suggested that the viral DNA was wrapped around a helical filament composed of the major core protein, and that the resulting nucleoprotein was packed into six rodlike elements.

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