scholarly journals Biochemical and immunohistochemical analysis of pectic polysaccharides in the cell walls of Arabidopsis mutant QUASIMODO 1 suspension-cultured cells: implications for cell adhesion

2005 ◽  
Vol 56 (422) ◽  
pp. 3171-3182 ◽  
Author(s):  
Edouard Leboeuf ◽  
Fabienne Guillon ◽  
Séverine Thoiron ◽  
Marc Lahaye
1996 ◽  
Vol 295 ◽  
pp. 195-208 ◽  
Author(s):  
Monica Fischer ◽  
Teresa F. Wegryzn ◽  
Ian C. Hallett ◽  
Robert J. Redgwell

2002 ◽  
Vol 115 (7) ◽  
pp. 1391-1402 ◽  
Author(s):  
Sirpa Aho ◽  
Laura Levänsuo ◽  
Outi Montonen ◽  
Csaba Kari ◽  
Ulrich Rodeck ◽  
...  

P120 catenin (p120ctn) belongs to the Armadillo family of proteins, which is implicated in cell-cell adhesion and signal transduction. Owing to alternative splicing and multiple translation initiation codons, several p120ctn isoforms can be expressed from a single gene. All p120ctn isoforms share the central Armadillo repeat domain but have divergent N- and C-termini. Little is known about the biological functions of the different isoforms. In this study, we examined the distribution of various p120ctn isoforms and the consequences of their expression in cultured cells of epidermal origin. Immunohistochemical analysis and western blotting revealed that melanocytes and melanoma cells primarily express the long isoform 1A, whereas keratinocytes express shorter isoforms, especially 3A, which localize to cell-cell adhesion junctions in a calcium-dependent manner. The shortest isoform 4A, which was detected in normal keratinocytes and melanocytes, was generally lost from cells derived from squamous cell carcinomas or melanomas. The C-terminal alternatively spliced exon B was present in the p120ctn transcripts in the colon, intestine and prostate, but was lost in several tumor tissues derived from these organs. To test whether p120ctn isoforms serve in distinct biological functions, we transiently transfected the expression constructs into melanoma cells (1205-Lu) and immortalized keratinocytes (HaCaT). Indeed, distinct domains of p120ctn are responsible for its different biological functions. The prominent branching phenotype was induced equally by isoforms 1A, 2A and 3A, whereas the shortest isoform 4A,which was devoid of the N-terminal domain, completely lacked this ability. Also, the exon-B-encoded sequences, as in the isoform 1AB, were sufficient to abolish the branching phenotype as induced by the isoform 1A. The induction of the branching phenotype cosegregated with the nuclear localization of the p120ctn isoforms 1A, 2A and 3A, whereas the isoforms 4A and 1AB, which were excluded from the nucleus, did not induce the branching phenotype. The N-terminal sequences that contain seven out of eight tyrosine residues,recently characterized as potential candidates for phosphorylation by Src kinase, are required for the nuclear localization and for the formation of the branching phenotype. Finally, expression of the p120ctn isoforms, which caused the branching phenotype, was associated with cellular relocalization of E-cadherin in HaCaT cells. Collectively, we have identified sequences within the p120ctn N-terminus that are prerequisites for both nuclear localization and the p120ctn-induced branching phenotype. Loss of the cytoplasmic pool of p120ctn from tumor cells suggests an important function for such isoforms in normal cells and tissues.


1993 ◽  
Vol 69 (1) ◽  
pp. 177-188 ◽  
Author(s):  
D. F. Gray ◽  
S. C. Fry ◽  
M. A. Eastwood

Uniformly 14C-labelled primary cell walls (14C-PCW) were purified from suspension-cultured cells of spinach (Spinacia oleracea L.) grown in a medium containing D-[U-14C]glucose. The approximate polymer composition of the 14C-PCW preparation (% total 14C) was homogalacturonan 30,rhamnogalacturonan 23, xyloglucan 10, other hemicelluloses 3, cellulose 21, lignin 0,14C-labelled protein < 3 and [14C]starch < 2. The degree of methyl esterification of the pectic polysaccharides was about 25%. The 14C-PCW contained about 4% O-acetyl and 3% non-volatile ester-linked residues. When tracer levels of these 14C-PCW were fed to rats, only about 18% of the 14C appeared in the faeces;negligible levels of 14C (0.07%) remained in the gut contents 4 d after feeding. Some 14C was present in the carcass. The results show that U-14C-labelled primary cell walls can be purified and radiochemically analysed by the methods developed here, and that primary cell walls are extensively fermented by the gut microflora of the rat.


1992 ◽  
Vol 84 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Stephen P. Lee ◽  
Baolong Zhu ◽  
Tony H. H. Chen ◽  
Paul H. Li

2020 ◽  
Author(s):  
Ian Sims ◽  
K Middleton ◽  
AG Lane ◽  
AJ Cairns ◽  
A Bacic

Microscopic examination of suspension-cultured cells of Phleum pratense L., Panicum miliaceum L., Phalaris aquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted by these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides. In contrast, suspension-cultured cells of Hordeum vulgare L. contained mostly undifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages consistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbohydrate, 14% protein and 6% inorganic material. The extracellular polysaccharides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses, five polysaccharides were identified: an arabinosylated xyloglucan (comprising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabinogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%), and a root-slime-like polysaccharide, which contained features of type-II arabinogalactans and glucuronomannans (65%).


2020 ◽  
Author(s):  
Ian Sims ◽  
K Middleton ◽  
AG Lane ◽  
AJ Cairns ◽  
A Bacic

Microscopic examination of suspension-cultured cells of Phleum pratense L., Panicum miliaceum L., Phalaris aquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted by these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides. In contrast, suspension-cultured cells of Hordeum vulgare L. contained mostly undifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages consistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbohydrate, 14% protein and 6% inorganic material. The extracellular polysaccharides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses, five polysaccharides were identified: an arabinosylated xyloglucan (comprising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabinogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%), and a root-slime-like polysaccharide, which contained features of type-II arabinogalactans and glucuronomannans (65%).


1968 ◽  
Vol 39 (3) ◽  
pp. 698-715 ◽  
Author(s):  
H. W. Israel ◽  
M. M. Salpeter ◽  
F. C. Steward

Cultured carrot explants, stimulated to grow rapidly in a medium containing coconut milk, were labeled with radioactive proline. After an initial period of absorption (8 hr for proline-3H; 24 hr for proline-14C) the tissue was allowed to grow for a further period of 6 days in a similar medium free from the radioactivity. Samples were prepared for electron microscopy and radioautography at the end of the absorption period and also after the further growth. The distribution of the products from the radioactive proline in the cells is shown by high-resolution radioautography and is rendered quantitative for the different regions of the cells. The results show that the combined label, which was present in the form of proline and the hydroxyproline derived from it, was all in the protoplasm, not in the cell walls. Any combined label that appeared to be over the cell walls is shown to be due to scatter from adjacent cytoplasmic sites. Initially the radioactivity was concentrated in nuclei, even more so in nucleoli, but it subsequently appeared throughout the ground cytoplasm and was also concentrated in the plastids. The significance of these observations for the general concept of a plant cell wall protein and for the special problem of growth induction in otherwise quiescent cells is discussed.


2002 ◽  
Vol 43 (11) ◽  
pp. 1314-1322
Author(s):  
Tsuneo Hakoyama ◽  
Tadashi Yokoyama ◽  
Hiroshi Kouchi ◽  
Ken-ichi Tsuchiya ◽  
Hisatoshi Kaku ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document