Incorporation of mammalian actin into microfilaments in plant cell nucleus.
BACKGROUND
Actin is an ancient molecule that shows more than 90% amino acid homology between mammalian and plant actins. The regions of the actin molecule that are involved in F-actin assembly are largely conserved, and it is likely that mammalian actin is able to incorporate into microfilaments in plant cells but there is no experimental evidence until now.


RESULTS
Visualization of microfilaments in onion bulb scale epidermis cells by different techniques revealed that rhodamine-phalloidin stained F-actin besides cytoplasm also in the nuclei whereas GFP-mouse talin hybrid protein did not enter the nuclei. Microinjection of fluorescently labeled actin was applied to study the presence of nuclear microfilaments in plant cells. Ratio imaging of injected fluorescent rabbit skeletal muscle actin and phalloidin staining of the microinjected cells showed that mammalian actin was able to incorporate into plant F-actin. The incorporation occurred preferentially in the nucleus and in the perinuclear region of plant cells whereas part of plant microfilaments, mostly in the periphery of cytoplasm, did not incorporate mammalian actin.


CONCLUSIONS
Microinjected mammalian actin is able to enter plant cell's nucleus, whereas incorporation of mammalian actin into plant F-actin occurs preferentially in the nucleus and perinuclear area.
Paves
Heiti
H
Laboratory of Molecular Genetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. heiti@kbfi.ee
Truve
Erkki
E
D008841:Actin Cytoskeleton / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008845:Microinjections; D008856:Microscopy, Fluorescence; D019697:Onions / Q000166:cytology / Q000378:metabolism*; D010590:Phalloidine / Q000737:chemistry; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012235:Rhodamines / Q000737:chemistry; D016608:Talin / Q000235:genetics / Q000378:metabolism
D000199:Actins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D012235:Rhodamines; D016608:Talin; D049452:Green Fluorescent Proteins; D010590:Phalloidine