GLP-1 is localized to the mitotic region of the C. elegans germ line

Development ◽  
1994 ◽  
Vol 120 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
S.L. Crittenden ◽  
E.R. Troemel ◽  
T.C. Evans ◽  
J. Kimble
Keyword(s):  
Membrane Protein ◽  
Germ Line ◽  
Integral Membrane Protein ◽  
Membrane Receptor ◽  
Down Regulation ◽  
Western Blots ◽  
Tip Cell ◽  
C Elegans ◽  
Cell Signal ◽  
Translational Level

In C. elegans, germline mitosis depends on induction by the somatic distal tip cell (DTC) and on activity of the glp-1 gene. Using antibodies to GLP-1 protein, we have examined GLP-1 on western blots and by immunocytochemistry. GLP-1 is tightly associated with membranes of mitotic germline cells, supporting its identification as an integral membrane protein. Furthermore, GLP-1 is localized within the germ line to the mitotic region, consistent with the model that GLP-1 acts as a membrane receptor for the distal tip cell signal. Unexpectedly, GLP-1 and the zone of mitosis extend further than the DTC processes. We present three models by which the DTC may influence GLP-1 activity and thereby determine the zone of mitosis. The spatial restriction of GLP-1 appears to be controlled at the translational level in hermaphrodites. We suggest that down-regulation of GLP-1 may be required to effect the transition from mitosis into meiosis.

scholarly journals Down-regulation in Multiple Human Cancers of a Novel Gene,DMHC, from 17q25.1 That Encodes an Integral Membrane Protein

2001 ◽  
Vol 92 (4) ◽  
pp. 417-422 ◽  
Author(s):  
Iwao Mikami ◽  
Haruhito Harada ◽  
Hisaki Nagai ◽  
Michiko Tsuneizumi ◽  
Yukiko Nobe ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Integral Membrane Protein ◽  
Down Regulation ◽  
Novel Gene ◽  
Human Cancers

scholarly journals Mutation of a putative sperm membrane protein in Caenorhabditis elegans prevents sperm differentiation but not its associated meiotic divisions.

1992 ◽  
Vol 119 (1) ◽  
pp. 55-68 ◽  
Author(s):  
S W L'Hernault ◽  
P M Arduengo
Keyword(s):  
Caenorhabditis Elegans ◽  
Membrane Protein ◽  
Molecular Basis ◽  
Close Association ◽  
Integral Membrane Protein ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Fibrous Body ◽  
Sperm Membrane ◽  
Internal Membrane Structure

Spermatogenesis in the nematode Caenorhabditis elegans uses unusual organelles, called the fibrous body-membranous organelle (FB-MO) complexes, to prepackage and deliver macromolecules to spermatids during cytokinesis that accompanies the second meiotic division. Mutations in the spe-4 (spermatogenesis-defective) gene disrupt these organelles and prevent cytokinesis during spermatogenesis, but do not prevent completion of the meiotic nuclear divisions that normally accompany spermatid formation. We report an ultrastructural analysis of spe-4 mutant sperm where the normally close association of the FB's with the MO's and the double layered membrane surrounding the FB's are both defective. The internal membrane structure of the MO's is also disrupted in spe-4 mutant sperm. Although sperm morphogenesis in spe-4 mutants arrests prior to the formation of spermatids, meiosis can apparently be completed so that haploid nuclei reside in an arrested spermatocyte. We have cloned the spe-4 gene in order to understand its role during spermatogenesis and the molecular basis of how mutation of this gene disrupts this process. The spe-4 gene encodes an approximately 1.5-kb mRNA that is expressed during spermatogenesis, and the sequence of this gene suggests that it encodes an integral membrane protein. These data suggest that mutation of an integral membrane protein within FB-MO complexes disrupts morphogenesis and prevents formation of spermatids but does not affect completion of the meiotic nuclear divisions in C. elegans sperm.

scholarly journals Platelets express a membrane protein complex immunologically related to the fibroblast fibronectin receptor and distinct from GPIIb/IIIa

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1535-1538 ◽  
Author(s):  
FG Giancotti ◽  
LR Languino ◽  
A Zanetti ◽  
G Peri ◽  
G Tarone ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Complex ◽  
Integral Membrane Protein ◽  
Human Platelets ◽  
Western Blots ◽  
Platelet Surface ◽  
Fibronectin Receptor ◽  
Glycoprotein Complex ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We have previously identified and characterized a membrane glycoprotein complex (GP150/135) that functions as fibronectin receptor (FN-R) in fibroblast adhesion. Here we report that an immunologically related protein complex is expressed at the surface of human platelets. Antibodies monospecific for the smaller subunit (GP135) of the fibroblast FN-R in fact specifically stained the platelet surface, as determined by FACS analysis, and reacted with a component of molecular weight (mol wt) 138,000 as shown in western blots of platelet membranes. Moreover, the same antibodies precipitated the 138,000 component together with a 160,000 protein, suggesting that the two molecules are associated in a supramolecular complex. A comparative analysis indicated that this protein complex is distinct from the GPIIb/IIIa complex, known to function as a receptor of wide specificity for fibrinogen, fibronectin, and von Willebrand factor. Differential extraction experiments revealed that the platelet 138,000 component is an integral membrane protein.

scholarly journals Symmetry breakage in the development of one-armed gonads in nematodes

Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 2129-2142 ◽  
Author(s):  
M.A. Felix ◽  
P.W. Sternberg
Keyword(s):  
Germ Line ◽  
Nematode Species ◽  
Cell Specification ◽  
Tip Cell ◽  
C Elegans ◽  
Cell Ablation ◽  
Intercellular Signalling ◽  
Anchor Cell ◽  
Hermaphrodite Gonad ◽  
Symmetry Breakage

Whereas the hermaphrodite gonad of Caenorhabditis elegans has two symmetric arms (didelphy), the female/hermaphrodite gonad of many nematode species features a single anterior arm (monodelphy). We examined how gonadal cell lineages and intercellular signalling evolve to generate these diverse structures. In C. elegans, the two arms develop symmetrically from two somatic precursor cells, Z1 (anterior) and Z4 (posterior). Each first gives rise to one distal tip cell (which promotes arm growth and germ line proliferation), two ovary precursors and three uterine precursors in the center of the developing gonad. In monodelphic species, Z1 and Z4 have different fates. The first visible asymmetry between them is in the relative timing of their divisions, followed by asymmetric cell movements. The putative posterior distal tip cell is then eliminated in all but one species by programmed cell death. In some species the posterior ovary precursors form a small vestigial posterior arm, the post-vulval sac; in other species, they stay undivided, or die. In Cephalobus sp. PS1197, the specific fate of Z4 progeny is induced by Z1 (or its daughters). In the uterus in C. elegans, symmetric lateral signalling between Z1.ppp and Z4.aaa renders them equally likely to become the anchor cell, which links the uterus to the vulva. In the different monodelphic species, anchor cell specification is biased, or fully fixed, to a descendant of either Z1 or Z4. Replacement regulation upon anchor cell ablation is conserved in some species, but lost in others, leading to a mosaic-type development. Differentiation between Z1 and Z4 is thus manifested at this later stage in the breakage of symmetry of cell interactions in the ventral uterus.

lag-2 may encode a signaling ligand for the GLP-1 and LIN-12 receptors of C. elegans

Development ◽  
1994 ◽  
Vol 120 (10) ◽  
pp. 2913-2924 ◽  
Author(s):  
S.T. Henderson ◽  
D. Gao ◽  
E.J. Lambie ◽  
J. Kimble
Keyword(s):  
In Situ Hybridization ◽  
Membrane Protein ◽  
Fusion Protein ◽  
Germ Line ◽  
Sequence Similarity ◽  
Notch Receptor ◽  
Null Mutant ◽  
Reporter Protein ◽  
C Elegans

The C. elegans lag-2 gene is required for several cell-cell interactions that rely on the receptors GLP-1 and LIN-12. In this paper, we report that lag-2 encodes a putative membrane protein with sequence similarity to Drosophila Delta, a proposed ligand for the Notch receptor. Furthermore, we show that the lag-2 promoter drives expression of a reporter protein in the signaling distal tip cell (DTC) of the DTC/germline interaction. By in situ hybridization, we have found that endogenous lag-2 mRNA is present in the DTC but not the germ line. One fusion protein, called LAG-2::beta-gal(intra), rescues a lag-2 null mutant and can be detected in both DTC and germ line. Taking these results together, we propose that lag-2 may encode a signaling ligand for GLP-1/LIN-12 and that the entire LAG-2 protein may be taken up into the receiving cell during induction by GLP-1 and lateral signaling by LIN-12.

scholarly journals Platelets express a membrane protein complex immunologically related to the fibroblast fibronectin receptor and distinct from GPIIb/IIIa

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1535-1538
Author(s):  
FG Giancotti ◽  
LR Languino ◽  
A Zanetti ◽  
G Peri ◽  
G Tarone ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Protein Complex ◽  
Integral Membrane Protein ◽  
Human Platelets ◽  
Western Blots ◽  
Platelet Surface ◽  
Fibronectin Receptor ◽  
Glycoprotein Complex ◽  
Von Willebrand ◽  
Willebrand Factor

We have previously identified and characterized a membrane glycoprotein complex (GP150/135) that functions as fibronectin receptor (FN-R) in fibroblast adhesion. Here we report that an immunologically related protein complex is expressed at the surface of human platelets. Antibodies monospecific for the smaller subunit (GP135) of the fibroblast FN-R in fact specifically stained the platelet surface, as determined by FACS analysis, and reacted with a component of molecular weight (mol wt) 138,000 as shown in western blots of platelet membranes. Moreover, the same antibodies precipitated the 138,000 component together with a 160,000 protein, suggesting that the two molecules are associated in a supramolecular complex. A comparative analysis indicated that this protein complex is distinct from the GPIIb/IIIa complex, known to function as a receptor of wide specificity for fibrinogen, fibronectin, and von Willebrand factor. Differential extraction experiments revealed that the platelet 138,000 component is an integral membrane protein.

Sign in / Sign up

Export Citation Format

Share Document