Synthesis of tertiary alkylphosphonate oligonucleotides through light-driven radical-polar crossover reactions

光エネルギーで新しい化学修飾核酸を合成 --核酸リン原子の第三級アルキル化に成功--. 京都大学プレスリリース. 2023-11-01.Chemical modification of nucleotides can improve the metabolic stability and target specificity of oligonucleotide therapeutics, and alkylphosphonates have been employed as charge-neutral replacements for naturally-occurring phosphodiester backbones in these compounds. However, at present, the alkyl moieties that can be attached to phosphorus atoms in these compounds are limited to methyl groups or primary/secondary alkyls, and such alkylphosphonate moieties can degrade during oligonucleotide synthesis. The present work demonstrates the tertiary alkylation of the phosphorus atoms of phosphites bearing two 2’-deoxynuclosides. This process utilizes a carbocation generated via a light-driven radical-polar crossover mechanism. This protocol provides tertiary alkylphosphonate structures that are difficult to synthesize using existing methods. The conversion of these species to oligonucleotides having charge-neutral alkylphosphonate linkages through a phosphoramidite-based approach was also confirmed in this study

Mite-antigen Stimulates MAL Expression in Peripheral Blood T Cells of Mite-sensitive Subjects

ABSTRACTBackgroundDifferential gene expression in CD3+ T cells from allergic patients stimulated with allergen will provide important information on the responses of T cells.MethodsAfter stimulation of peripheral blood mononuclear cells (PBMCs) with mite extracts, levels of gene transcription were examined in CD3+ T cells from allergic patients.ResultsStimulation of PBMCs from mite specific IgE positive subjects resulted in specific upregulation of MAL transcription levels that was mediated by IL-4 secretion. The MAL protein in IL-4 stimulated primary T cells preferentially localized in glycolipid-enriched membrane (GEM) microdomains. When MAL was exogenously expressed in primary T cells, CD3ζ was concomitantly enriched, along with the expression of MAL, in GEM microdomains.ConclusionsGEMs are important for the formation and stabilization of TCR signaling complexes. Therefore, MAL may play a role in the formation of GEMs in activated T cells and the high expression of MAL may contribute to Th2 immune response

Partial Deduction In Disjunctive Logic Programming

This paper presents a partial deduction method in disjunctive logic programming. Partial deduction in normal logic programs is based on unfolding between normal clauses, hence it is not applicable to disjunctive logic programs in general. Then we introduce a new partial deduction technique, called disjunctive partial deduction, which preserves the minimal model semantics of positive disjunctive programs and the stable model semantics of normal disjunctive programs. From the procedural side, disjunctive partial deduction is combined with a bottom-up proof procedure of disjunctive logic programs, and top-down partial deduction is introduced for query optimization. Disjunctive partial deduction is also applied to optimizing abductive logic programs and compiling propositional disjunctive programs. / 1. INTRODUCTIO