An early developmental phase of pp60c-src expression in the neural ectoderm

Maness, Patricia F.; Sorge, Laurie K.; Fults, Daniel W.

doi:10.1016/0012-1606(86)90350-7

Cited by 55 publications

(21 citation statements)

References 29 publications

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“…Low levels of pp6Ocsrc or c-src RNA have been detected in nearly all vertebrate cells and tissues examined, but a few specialized types of cells express much greater levels of pp60-src than other cell types (27,37,55,60). In the developing central nervous system, a large increase in pp6Ocsrc expression occurs at the onset of neuronal differentiation (15,21,45,47,48,64,71). pp6O -src levels are highest in certain postmitotic neurons undergoing dynamic changes in their spatial organization, such as the neuroepithelial cells that form the folding edge of the developing neural tube (48) and tracts of growing axonal processes in the developing retina and cerebellum (21,64).…”

Section: Resultsmentioning

confidence: 99%

Elevated expression of pp60c-src alters a selective morphogenetic property of epithelial cells in vitro without a mitogenic effect.

Warren¹,

Handel²,

Nelson³

1988

Mol. Cell. Biol.

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Madin-Darby canine kidney (MDCK) cells are highly differentiated and have retained the morphogenetic properties necessary to form polarized, multicellular epithelial structures (cysts) in vitro that resemble epithelial tissues in vivo. We introduced the c-src gene into MDCK cells to elevate the level of the plasma membrane-associated cellular tyrosine kinase, pp60Or(, to levels two-to ninefold higher than that expressed in parent MDCK cells. Our results revealed a highly discriminatory biological action of pp6C-src on the morphogenetic properties of MDCK cells. Elevated expression of pp60`src conferred on MDCK cells the ability to undergo dramatic changes of cell shape that includes the formation of long cell processes (100 to 200 ,um), never observed in control MDCK cells. The morphogenesis of multicellular epithelial cysts was altered by elevated levels of pp60`csrc and led to predictable distortions of their three-dimensional architecture. However, these cells established morphologically normal cell polarity, formed adhesive epithelial cell-cell contacts indistinguishable from those of control MDCK cells, and exhibited neither focus-forming ability or anchorageindependent growth potential. Finally, we showed that MDCK cells expressing elevated levels of pp60lj'CC exhibit increased phosphorylation of a more limited number of phosphotyrosine-containing proteins than MDCK cells expressing pp6vS'v. We suggest that a natural function of pp60`cu'c is to regulate the morphogenetic properties which determine the shape of differentiated cells and multicellular structures.The cellular tyrosine kinase, pp6O-src, is structurally homologous to the transforming protein of the Rous sarcoma virus, pp6Ov-src, which induces morphological alterations and uncontrolled proliferation of cells. However, the natural biological function of pp6O-src is unknown (4,5,34,35,66,67).The c-src gene has been assayed for biological activity almost exclusively by transformation assays that detect genes which lead to uncontrolled proliferation of cells (9,36,38,41,44,56,57,61). Elevated levels of pp6O-src do not transform chicken or rat fibroblasts in vitro (36, 56), although very high levels of pp60c-src have weak focus-inducing activity in NIH 3T3 cells (38). Thus, pp60f-src can partially mimic the transforming action of pp6Ov-src, but only under exceptional circumstances (34). Since elevated pp60c-src expression in vivo is most abundant in differentiated cells that cannot divide (15,21,45,64,71; also see Discussion), it is possible that pp60-src has a nonmitogenic natural function which does not manifest itself in transformation assays.We have developed a simple in vitro biological assay that detects nonmitogenic, morphoregulatory activities of pp6Osrc kinases (72). The assay is based on the ability of MadinDarby canine kidney (MDCK) cells to establish specific cell-cell contacts and to generate tissuelike multicellular structures (cysts) composed of polarized epithelial monolayers (10,11,30,52,59,70). We have shown previously that low-leve...

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Section: Resultsmentioning

confidence: 99%

Elevated expression of pp60c-src alters a selective morphogenetic property of epithelial cells in vitro without a mitogenic effect.

Warren¹,

Handel²,

Nelson³

1988

Mol. Cell. Biol.

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Section: Introductionmentioning

confidence: 99%

“…Although much of the work on tyrosine kinases has focused on growth regulation, recent findings in the nonproliferating cells of the central nervous system demonstrate the presence of relatively large amounts of tyrosine kinase activity (2, 3). For example, the c-src gene product, pp6O src, is widely distributed in the adult rat brain (4) and is expressed throughout brain development (5)(6)(7)(8).Receptors for insulin and insulin-like growth factor 1 (IGF-1) are also present in specific brain regions (9)(10)(11)(12)(13)). Both receptors demonstrate ligand-controlled autophosphorylation on specific tyrosines and tyrosine phosphorylation of endogenous proteins (14-17), although the distribution of the two receptor types differs in the rat brain (12,13,18).…”

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confidence: 99%

Location of phosphotyrosine-containing proteins by immunocytochemistry in the rat forebrain corresponds to the distribution of the insulin receptor.

Moss

Unger

Moxley

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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Cellular regulation by certain growth factor receptors and protooncogene products involves tyrosine kinase activity with the resultant tyrosine phosphorylation of protein substrates. In the present report we describe the distribution of phosphotyrosine-containing material detected by immunoytochemistry (ICC) in the rat forebrain. Specificity of the affinity-purified antibody against phosphotyrosine used in the ICC technique was demonstrated by the ability of phosphotyrosine and p-nitrophenyl phosphate but not phosphoserine, phosphothreonine, or L-tyrosine to inhibit the immunostaining reaction. With ICC, relatively high amounts of phosphotyrosine-positive material were observed in neurons in specific structures that included the supraoptic, paraventricular, and arcuate nuclei; the median eminence; medial habenula; subfornical organ; and piriform cortex. Moderate to high amounts were present in the cerebral cortical layers II-IV and in the pyramidal cell layer of the hippocampus. Small to moderate amounts were detected in a few other locations. Glial elements showed minimal staining. Other areas of the rat forebrain failed to react with this antibody. Importantly, the distribution of the areas positive for phosphotyrosine agreed to a remarkable extent with the distribution of the brain insulin receptor, which itself has tyrosine kinase activity. These findings suggest a relationship between the insulin receptor and the increased phosphotyrosine content of these neurons and support the concept that the brain insulin receptor is active in vivo.A number of growth factor receptors and protein products of retroviral oncogenes and protooncogenes are proteintyrosine kinases (1). This enzymatic activity apparently plays an important role in the mediation of the actions of these regulatory proteins (1,2). Although much of the work on tyrosine kinases has focused on growth regulation, recent findings in the nonproliferating cells of the central nervous system demonstrate the presence of relatively large amounts of tyrosine kinase activity (2, 3). For example, the c-src gene product, pp6O src, is widely distributed in the adult rat brain (4) and is expressed throughout brain development (5)(6)(7)(8).Receptors for insulin and insulin-like growth factor 1 (IGF-1) are also present in specific brain regions (9)(10)(11)(12)(13)). Both receptors demonstrate ligand-controlled autophosphorylation on specific tyrosines and tyrosine phosphorylation of endogenous proteins (14-17), although the distribution of the two receptor types differs in the rat brain (12,13,18).Little information is available on the in vivo activation of these kinases in the central nervous system. Previous work has used brain tissue extracts to examine tyrosine kinase activity (19), an approach that does not provide direct evidence of in vivo tyrosine kinase activity nor does it establish the precise location of areas rich in tyrosine phosphorylation.In the present investigation, we have examined the rat forebrain with an immunocytochemical technique (I...

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“…These findings have given us valuable information about the possible in vivo function of these genes, as well as the nature of molecular mechanisms underlying mammalian development (MOiler, 1983;Jakobovits et al, 1985;Mason et al, 1985;Maness et al, 1986;Miiller et al, 1986;Emilia et al, 1986; for review see Adamson, 1987). Genes regulated by growth factors are of particular interest in this regard, since their pattern of expression may give insights into the in vivo role of growth factors during embryogenesis.…”

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confidence: 99%

Developmental expression of 2ar (osteopontin) and SPARC (osteonectin) RNA as revealed by in situ hybridization

Nomura¹,

Wills²,

Edwards³

et al. 1988

The Journal of Cell Biology

491

244

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Abstract. 2ar has been identified as a gene inducible by tumor promoters and growth factors in a variety of cultured mouse cell lines (Smith, J. H., and D. T. Denhardt. 1987. J. Cell. Biochem. 34:13-22 262:2900-3907.). In this paper we use Northern blot analysis and in situ hybridization to localize expression of 2ar during mouse embryogenesis. 2ar RNA is first detected in developing limb bones and calvaria at 14.5 d p.c., in a population of cells distinct from those expressing SPARC (osteonectin). High levels of 2ar expression are also seen in the bone marrow-derived granulated metrial gland cells of the deciduum and placenta, and in a number of epithelial tissues, including embryonic and postnatal kidney tubules, uterine epithelium and sensory epithelium of the embryonic ear. The temporal and spatial pattern of 2ar expression seen in vivo suggests that the protein plays a wider role than previously realized, in processes which are not confined to bone development.

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An early developmental phase of pp60c-src expression in the neural ectoderm

Cited by 55 publications

References 29 publications

Elevated expression of pp60c-src alters a selective morphogenetic property of epithelial cells in vitro without a mitogenic effect.

Elevated expression of pp60c-src alters a selective morphogenetic property of epithelial cells in vitro without a mitogenic effect.

Location of phosphotyrosine-containing proteins by immunocytochemistry in the rat forebrain corresponds to the distribution of the insulin receptor.

Developmental expression of 2ar (osteopontin) and SPARC (osteonectin) RNA as revealed by in situ hybridization

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