Background: Certain members of the Camelidae family produce a special type of antibody with only one heavy chain. The antigen binding domains are the smallest functional fragments of these heavy-chain only antibodies and as a consequence have been termed nanobodies. Discovery of these nanobodies has allowed the development of a number of therapeutic proteins and tools.In this study a class of nanobodies fused to fluorescent proteins (chromobodies), and therefore allowing antigen-binding
and visualisation by fluorescence, have been used. Such chromobodies can be expressed in living cells and used asgenetically encoded immunocytochemical markers.
Results: Here a modified version of the commercially available Actin-Chromobody® as a novel tool for visualising actindynamics in tobacco leaf cells was tested. The actin-chromobody binds to actin in a specific manner. Treatment withlatrunculin B, a drug which disrupts the actin cytoskeleton through inhibition of polymerisation results in loss offluorescence after less than 30 min but this can be rapidly restored by washing out latrunculin B and thereby allowing the actin filaments to repolymerise.
To test the effect of the actin-chromobody on actin dynamics and compare it to one of the conventional labelling probes, Lifeact, the effect of both probes on Golgi movement was studied as the motility of Golgi bodies is largelydependent on the actin cytoskeleton. With the actin-chromobody expressed in cells, Golgi body movement was sloweddown but the manner of movement rather than speed was affected less than with Lifeact.
Conclusions: The actin-chromobody technique presented in this study provides a novel option for in vivo labelling ofthe actin cytoskeleton in comparison to conventionally used probes that are based on actin binding proteins.The actin-chromobody is particularly beneficial to study actin dynamics in plant cells as it does label actin without impairing dynamic movement and polymerisation of the actin filaments.
Rocchetti, AHawes, Chris
Faculty of Health and Life Sciences\Department of Biological and Medical SciencesFaculty of Health and Life Sciences
Year of publication: 2014Date of RADAR deposit: 2014-07-07