scholarly journals The UNC-112 Gene in Caenorhabditis elegansEncodes a Novel Component of Cell–Matrix Adhesion Structures Required for Integrin Localization in the Muscle Cell Membrane

2000 ◽  
Vol 150 (1) ◽  
pp. 253-264 ◽  
Author(s):  
Teresa M. Rogalski ◽  
Gregory P. Mullen ◽  
Mary M. Gilbert ◽  
Benjamin D. Williams ◽  
Donald G. Moerman

Embryos homozygous for mutations in the unc-52, pat-2, pat-3, and unc-112 genes of C. elegans exhibit a similar Pat phenotype. Myosin and actin are not organized into sarcomeres in the body wall muscle cells of these mutants, and dense body and M-line components fail to assemble. The unc-52 (perlecan), pat-2 (α-integrin), and pat-3 (β-integrin) genes encode ECM or transmembrane proteins found at the cell–matrix adhesion sites of both dense bodies and M-lines. This study describes the identification of the unc-112 gene product, a novel, membrane-associated, intracellular protein that colocalizes with integrin at cell–matrix adhesion complexes. The 720–amino acid UNC-112 protein is homologous to Mig-2, a human protein of unknown function. These two proteins share a region of homology with talin and members of the FERM superfamily of proteins. We have determined that a functional UNC-112::GFP fusion protein colocalizes with PAT-3/β-integrin in both adult and embryonic body wall muscle. We also have determined that UNC-112 is required to organize PAT-3/β-integrin after it is integrated into the basal cell membrane, but is not required to organize UNC-52/perlecan in the basement membrane, nor for DEB-1/vinculin to localize with PAT-3/β-integrin. Furthermore, UNC-112 requires the presence of UNC-52/perlecan and PAT-3/β-integrin, but not DEB-1/vinculin to become localized to the muscle cell membrane.

1978 ◽  
Vol 76 (1) ◽  
pp. 76-86 ◽  
Author(s):  
J Rosenbluth

Analysis of freeze-fractured earthworm body wall muscle reveals distinctive trough-shaped concavities in the protoplasmic leaflet of the muscle cell membrane which contain diagonally oriented rows of particles sometimes in highly ordered arrays. The troughs correspond to the concave postjunctional patches of sarcolemma seen previously in thin sections of myoneural junctions identified as cholinergic, and the intramembranous particles within the troughs correspond in concentration and arrangement to granular elements present in the outer dense lamina of the postjunctional membrane which were interpreted as acetylcholine receptors. The freeze-fracture data provide a more accurate picture of the arrangement of these putative receptors within the plane of the membrane, and indicate also that they extend into the membrane at least as far as its hydrophobic layer.


Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 483-498
Author(s):  
J Ahnn ◽  
A Fire

Abstract We have used available chromosomal deficiencies to screen for genetic loci whose zygotic expression is required for formation of body-wall muscle cells during embryogenesis in Caenorhabditis elegans. To test for muscle cell differentiation we have assayed for both contractile function and the expression of muscle-specific structural proteins. Monoclonal antibodies directed against two myosin heavy chain isoforms, the products of the unc-54 and myo-3 genes, were used to detect body-wall muscle differentiation. We have screened 77 deficiencies, covering approximately 72% of the genome. Deficiency homozygotes in most cases stain with antibodies to the body-wall muscle myosins and in many cases muscle contractile function is observed. We have identified two regions showing distinct defects in myosin heavy chain gene expression. Embryos homozygous for deficiencies removing the left tip of chromosome V fail to accumulate the myo-3 and unc-54 products, but express antigens characteristic of hypodermal, pharyngeal and neural development. Embryos lacking a large region on chromosome III accumulate the unc-54 product but not the myo-3 product. We conclude that there exist only a small number of loci whose zygotic expression is uniquely required for adoption of a muscle cell fate.


2020 ◽  
Vol 502 ◽  
pp. 110387
Author(s):  
Linda Irons ◽  
Huang Huang ◽  
Markus R. Owen ◽  
Reuben D. O’Dea ◽  
Gerald A. Meininger ◽  
...  

1985 ◽  
Vol 101 (4) ◽  
pp. 1532-1549 ◽  
Author(s):  
G R Francis ◽  
R H Waterston

The body wall muscle cells of Caenorhabditis elegans contain an obliquely striated myofibrillar lattice that is associated with the cell membrane through two structures: an M-line analogue in the A-band and a Z-disc analogue, or dense-body, in the I-band. By using a fraction enriched in these structures as an immunogen for hybridoma production, we prepared monoclonal antibodies that identify four components of the I-band as determined by immunofluorescence and Western transfer analysis. A major constituent of the dense-body is a 107,000-D polypeptide that shares determinants with vertebrate alpha-actinin. A second dense-body constituent is a more basic and antigenically distinct 107,000-D polypeptide that is localized to a narrow domain of the dense-body at or subjacent to the plasma membrane. This basic dense-body polypeptide is also found at certain cell boundaries where thin filaments in half-bands terminate at membrane-associated structures termed attachment plaques. A third, unidentified antigen is also found closely apposed to the cell membrane in regions of not only the dense-body and attachment plaque, but also the M-line analogue. Finally, a fourth high molecular weight antigen, composed of two polypeptides of approximately 400,000-D, is localized to the I-band regions surrounding the dense-body. The attachment of the dense-body to the cell surface and the differential localization of the dense-body-associated antigens suggest a model for their organization in which the unidentified antigen is a cell surface component, and the two 107,000-D polypeptides define different cytoplasmic domains of the dense-body.


2002 ◽  
Vol 157 (4) ◽  
pp. 665-677 ◽  
Author(s):  
Kenneth R. Norman ◽  
Donald G. Moerman

Acommon feature of multicellular animals is the ubiquitous presence of the spectrin cytoskeleton. Although discovered over 30 yr ago, the function of spectrin in nonerythrocytes has remained elusive. We have found that the spc-1 gene encodes the only α spectrin gene in the Caenorhabditis elegans genome. During embryogenesis, α spectrin localizes to the cell membrane in most if not all cells, starting at the first cell stage. Interestingly, this localization is dependent on β spectrin but not βHeavy spectrin. Furthermore, analysis of spc-1 mutants indicates that β spectrin requires α spectrin to be stably recruited to the cell membrane. Animals lacking functional α spectrin fail to complete embryonic elongation and die just after hatching. These mutant animals have defects in the organization of the hypodermal apical actin cytoskeleton that is required for elongation. In addition, we find that the process of elongation is required for the proper differentiation of the body wall muscle. Specifically, when compared with myofilaments in wild-type animals the myofilaments of the body wall muscle in mutant animals are abnormally oriented relative to the longitudinal axis of the embryo, and the body wall muscle cells do not undergo normal cell shape changes.


Cell ◽  
1990 ◽  
Vol 63 (5) ◽  
pp. 907-919 ◽  
Author(s):  
Michael Krause ◽  
Andrew Fire ◽  
Susan White Harrison ◽  
James Priess ◽  
Harold Weintraub

2021 ◽  
Vol 22 (10) ◽  
pp. 5144
Author(s):  
Antonín Sedlář ◽  
Martina Trávníčková ◽  
Pavla Bojarová ◽  
Miluše Vlachová ◽  
Kristýna Slámová ◽  
...  

Galectin-3 (Gal-3) is a β-galactoside-binding protein that influences various cell functions, including cell adhesion. We focused on the role of Gal-3 as an extracellular ligand mediating cell-matrix adhesion. We used human adipose tissue-derived stem cells and human umbilical vein endothelial cells that are promising for vascular tissue engineering. We found that these cells naturally contained Gal-3 on their surface and inside the cells. Moreover, they were able to associate with exogenous Gal-3 added to the culture medium. This association was reduced with a β-galactoside LacdiNAc (GalNAcβ1,4GlcNAc), a selective ligand of Gal-3, which binds to the carbohydrate recognition domain (CRD) in the Gal-3 molecule. This ligand was also able to detach Gal-3 newly associated with cells but not Gal-3 naturally present on cells. In addition, Gal-3 preadsorbed on plastic surfaces acted as an adhesion ligand for both cell types, and the cell adhesion was resistant to blocking with LacdiNAc. This result suggests that the adhesion was mediated by a binding site different from the CRD. The blocking of integrin adhesion receptors on cells with specific antibodies revealed that the cell adhesion to the preadsorbed Gal-3 was mediated, at least partially, by β1 and αV integrins—namely α5β1, αVβ3, and αVβ1 integrins.


2007 ◽  
Vol 213 (3) ◽  
pp. 565-573 ◽  
Author(s):  
Allison L. Berrier ◽  
Kenneth M. Yamada

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