Hüsken K, Wiesenfahrt T, Abraham C, Windoffer R, Bossinger O, Leube RE. 2008
Maintenance of the intestinal tube in Caenorhabditis elegans: the role of the intermediate filament protein IFC-2.
Differentiation 8:881-96.
The C. elegans intestinal lumen is
surrounded by a dense cytoplasmic network that is laterally attached to the
junctional complex and is referred to as the endotube. It localizes to the terminal
web region which anchors the microvillar actin filament bundles and is
particularly rich in intermediate filaments. To examine their role in
intestinal morphogenesis and function, C.
elegans reporter strains were generated expressing
intestine-specific CFP-tagged intermediate filament polypeptide IFB-2. When
these animals were treated with dsRNA against RNA encoding intestinal
intermediate filament polypeptide IFC-2 multiple bubbleshaped invaginations of
the endotube into the enterocytic cytoplasm developed with increasing age. The
irregularly widened lumen was still surrounded by a continuous IFB- 2::CFP-labelled
layer. Junctional complexes were ultrastructurally and functionally normal and
the apical domain of intestinal cells was also not altered. These observations
demonstrate that IFC-2 is important for structural maintenance of the
intestinal tube but is not needed for establishment of the endotube and
epithelial cell polarity. The observed reduction of progeny in ifc-2 RNAi-treated
animals, on the other hand, suggests that digestive and/or metabolic activities
of the intestine, which are central to the growth and reproduction of the
animal, become impaired when the shape of the intestinal tube is perturbed.
click animated previews to open full size
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Movie 1. Animated 3D-reconstruction of IFB-2::CFP fluorescence in the anterior intestinal ring (corresponding Fig. 3A). Movie 2. Animated 3D-reconstruction of IFB-2::CFP fluorescence in the posterior intestinal rings (corresponding Fig. 3B). Movie 3. Animated 3D-reconstructions of IFB-2::CFP fluorescence and Texas Redlabeled dextran in wild type worms that had been fed the dextran (corresponding Fig. 7A-A''). Movie 4.
Animated 3D-reconstructions of IFB-2::CFP fluorescence and Texas
Redlabeled dextran in ifc-2 RNAi treated worms that had been fed the
dextran (correspondingFig. 7B-B'').
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