Keio University · Medicine
Professor Junichi Sasaki's research lab specializes in molecular virology and RNA biology, with a focus on unconventional translation mechanisms in positive-sense RNA viruses, particularly those infecting insects. The lab investigates internal ribosome entry site (IRES)-mediated translation initiation, revealing that some viral capsid proteins are synthesized not from an AUG start codon but via alternative mechanisms involving non-AUG initiation, such as glutamine as the initiating amino acid. The lab also explores the structural and biochemical properties of bacterial cell wall components, particularly peptidoglycans containing D- and L-amino acids like 2,4-diaminobutyric acid, contributing to microbial taxonomy and cell wall biosynthesis. Their work bridges virology, translation biology, and microbial biochemistry, using biochemical and molecular techniques to uncover fundamental mechanisms of gene expression and microbial cell wall diversity.
Figures are computed from collected data and may differ slightly.
AUG-unrelated translation initiation was found in an insect picorna-like virus, Plautia stali intestine virus (PSIV). The positive-strand RNA genome of the virus contains two nonoverlapping open reading frames (ORFs). The capsid protein gene is located in the 3'-proximal ORF and lacks an AUG initiation codon. We examined the translation mechanism and the initiation codon of the capsid protein gene by using various dicistronic and monocistronic RNAs in vitro. The capsid protein gene was translate
Protein synthesis is believed to be initiated with the amino acid methionine because the AUG translation initiation codon of mRNAs is recognized by the anticodon of initiator methionine transfer RNA. A group of positive-stranded RNA viruses of insects, however, lacks an AUG translation initiation codon for their capsid protein gene, which is located at the downstream part of the genome. The capsid protein of one of these viruses, Plautia stali intestine virus, is synthesized by internal ribosome
An HPLC procedure which separates D- and L-amino acid isomers was applied to an analysis of peptidoglycan of 2,4-diaminobutyric acid (DAB)-containing actinomycetes. The cell wall peptidoglycans of species of the genera Agromyces, Clavibacter and Rathayibacter contain DAB and have been differentiated principally by their menaquinone profile. These peptidoglycans are known to be identical in structure, all being of the B2 gamma type, possessing both D- and L-DAB. The type strains of all the subspe
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