AsianScientist (Sep. 19, 2016) – Scientists in Japan have developed a sensitive fluorescent antibody probe that can be used to detect a specific type of protein modification in living cells. Their work was published in the Journal of Molecular Biology.
Genomic integrity in living cells is maintained by packaging of nuclear DNA into chromatin, which protects it from damage while also controlling gene replication and expression. Histones are the primary protein components of chromatin, and their post-translational modifications regulate chromatin structure.
Among the modifications, methylation of histone H4 at lysine 20 (H4K20) exists in three states, mono-, di- and trimethylation, each of which have distinct biological roles. Conventional techniques used to study regulation by histone modifications are limited to fixed (dead) cells, thus preventing assessment of histone modification in single, living cells.
To observe histone modification in living cells, scientists led by Professor Aktsuki Kimura from the Institute of Innovative Research, Tokyo Institute of Technology, generated a live-cell imaging probe for sensitive monitoring of the intracellular spatiotemporal dynamics of H4K20 monomethylation (H4K20me1). The probe, called modification-specific intracellular antibody or mintbody, is a single-chain variable fragment tagged with a fluorescent protein that demonstrates high specificity for H4K20me1 over di- and trimethylation in living yeast, mammalian cells, and even multicellular organisms.
In a roundworm Caenorhabditis elegans model, Kimura and colleagues showed that the mintbody could be used to monitor changes in H4K20me1 over the cell cycle and localization of dosage-compensated X chromosomes without disrupting cell function. Thus, the new mintbody can be used to overcome the challenges associated with visualizing and tracking histone modifications directly in living cells.
The article can be found at: Sato et al. (2016) A Genetically Encoded Probe for Live-Cell Imaging of H4K20 Monomethylation.
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Source: Tokyo Institute of Technology.
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