Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We present the nucleotide sequence of the coding region of the rat c-rasH-1 gene and a partial sequence analysis of the rat c-rasH-2 gene. By comparing these sequences with the Harvey murine sarcoma virus ras gene, we predict that the p21 protein encoded by the Harvey virus differs from the cellular c-rasH-1-encoded p21 at only two amino acids; those at positions 12 and 59. Alterations at each of these positions may play a role in activating the viral p21 protein. The c-rasH-2 gene is likely to be a nonfunctional pseudogene because it lacks introns, cannot be activated to transform NIH 3T3 cells, and differs in sequence from both c-rasH-1 and v-rasH at several base pair positions.
Mol Cell Biol 1986 May
PMID:Nucleotide sequence of the two rat cellular rasH genes. 302 1

We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-rasH transforming protein, which is closely related to the cellular rasH protein. The mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic domain that were dispensable for transformation and six other segments that were required for transformation. Segments that were necessary for guanosine nucleotide (GDP) binding corresponded to three of the segments that were essential for transformation; two of the three segments share strong sequence homology with other purine nucleotide-binding proteins. Loss of GDP binding was associated with apparent instability of the protein. Lesions in two of the three other required regions significantly reduced GDP binding, while small lesions in the last required region did not impair GDP binding or membrane localization. We speculate that this latter region interacts with the putative cellular target of ras. The results suggest that transforming ras proteins require membrane localization, guanosine nucleotide binding, and an additional undefined function that may represent interaction with their target.
Mol Cell Biol 1986 Jul
PMID:Mutational analysis of a ras catalytic domain. 302 43

We isolated a human gene (designated c-ros-1) homologous to the v-ros sequence of UR2 sarcoma virus. Ten exons, 1,414 base pairs spanning 26 kilobases, contained a tyrosine kinase domain, a transmembrane domain, and a part of an extracellular domain carrying an N glycosylation site which was not acquired by UR2 sarcoma virus. The predicted structure of c-ros-1 is unique among the src family and clearly distinct from the human insulin receptor.
Mol Cell Biol 1986 Aug
PMID:Human c-ros-1 gene homologous to the v-ros sequence of UR2 sarcoma virus encodes for a transmembrane receptorlike molecule. 302 56

We used the sensitive gel electrophoresis DNA-binding assay and DNase I footprinting to detect at least two protein factors (EFI and EFII) that bound specifically to the Rous sarcoma virus (RSV) enhancer in vitro. These factors were differentially extracted from quail cell nuclei, recognized different nucleotide sequences in the U3 region of the RSV long terminal repeat, and appeared to bind preferentially to opposite DNA strands as monitored by the DNase I protection assay. The EFI- and EFII-protected regions within U3 corresponded closely to sequences previously demonstrated by deletion mutagenesis to be required for enhancer activity, strongly suggesting a functional significance for these proteins. Only weak homologies between other enhancer consensus sequence motifs and the EFI and EFII recognition sites were observed, and other viral enhancers from simian virus 40 and Moloney murine sarcoma virus did not compete effectively with the RSV enhancer for binding either factor.
Mol Cell Biol 1987 Feb
PMID:At least two nuclear proteins bind specifically to the Rous sarcoma virus long terminal repeat enhancer. 302 68

The cytoskeletal protein talin was found to undergo enhanced phosphorylation at tyrosine residues in chicken embryo fibroblasts following transformation by Rous sarcoma virus. An increase in the tyrosine phosphorylation of talin was also observed within 6 h in cells infected by the temperature-sensitive mutant tsNY68 after a shift from the nonpermissive to the permissive temperature. The overall extent of phosphorylation was 0.07 mol of phosphate per mol of talin and was not appreciably altered by transformation. In uninfected cells talin was shown to be phosphorylated at multiple sites by tryptic peptide mapping. Following transformation most of these sites remained phosphorylated, to the same or to a lesser extent, while novel, phosphotyrosine-containing phosphopeptides appeared. Talin was phosphorylated at tyrosine in cells infected by Rous sarcoma virus mutants which induce altered or partial transformation morphologies; thus the increased phosphorylation of talin at tyrosine occurred irrespective of the morphology induced. Transformation by Y73 also induced elevated levels of phosphotyrosine in talin, whereas transformation by the avian erythroblastosis and Fujinami sarcoma viruses did not.
Mol Cell Biol 1987 Jan
PMID:Phosphorylation of talin at tyrosine in Rous sarcoma virus-transformed cells. 303 68

A cis-acting enhancer element has been detected within the gag gene of several avian retroviruses, including Rous sarcoma virus, Fujinami sarcoma virus, and the endogenous Rous-associated virus-0. A consensus enhancer core sequence, GTGGTTTG, is present in all of these viral genomes, approximately 900 bases downstream from the site of initiation of transcription. When an internal fragment derived from the gag gene of any of these viruses (spanning nucleotides 533 to approximately 1149) was inserted into a plasmid containing the chloramphenicol acetyltransferase (cat) gene under control of the simian virus 40 promoter, 9- or 21-fold enhancement of CAT expression was observed after transfection into mouse L cells and chicken embryo fibroblasts, respectively. This enhancement was not dependent on the position of insertion of the gag fragment into the plasmid. However, there was a strong dependence on orientation, with higher levels of CAT expression in constructs in which the 5' end of the gag fragment was nearest to the promoter, suggesting a possible negative regulatory element at the 3' end of this fragment. Deletion of the 3' end of the insert resulted in a gag fragment, containing nucleotides 533 to 1017, which enhanced expression equally in either orientation. When the gag fragment was inserted into a plasmid containing the cat gene under the control of an intact Rous sarcoma virus long terminal repeat, it induced a two- to threefold increase in CAT activity and CAT mRNA levels. Translation of the gag fragment did not appear to be necessary for the observed enhancement, since two insertional mutations resulting in frameshifts in the gag insert did not affect CAT expression. However, deletion of a 330-base internal fragment from the gag insert restored a basal level of CAT activity. These results suggest that retroviruses have regulatory elements within their genes distinct from those in the long terminal repeats that flank the genes.
Mol Cell Biol 1987 Jan
PMID:cis-acting regulatory elements within gag genes of avian retroviruses. 303 70

NRK cells infected with a temperature-sensitive Kirsten sarcoma virus (ts371 KSV) are transformed at 36 degrees C, but are untransformed at 41 degrees C which inactivates the abnormally thermolabile oncogenic p21Ki product of the viral Ki-ras gene. At 41 degrees C, tsKSV-infected NRK cells were arrested in G0/G1 when incubated in serum-free medium, but could then be stimulated to transit G1, replicate DNA, and divide by adding serum at 41 degrees C or dropping the temperature to a p21-activating 36 degrees C without adding serum. When quiescent cells at 41 degrees C were stimulated to transit G1 in serum-free medium by activating p21 at 36 degrees C and then shifted back to the p21-inactivating 41 degrees C in the mid-S phase, they continued replicating DNA but could not transit G2. Reactivating p21 in the G2-arrested cells by once again lowering the temperature to 36 degrees C stimulated a rapid entry into mitosis. By contrast, while serum-stimulated quiescent G0 cells at 41 degrees C replicate DNA and divide, serum did not induce G2-arrested cells to enter mitosis, indicating that serum growth factors may trigger events in the G1 phase that ultimately determine G2 transit. These observations made with the viral ras product suggest that cellular ras proto-oncogene products have a role in G2 transit of normal cells.
Mol Cell Biol 1987 Jan
PMID:The viral Ki-ras gene must be expressed in the G2 phase if ts Kirsten sarcoma virus-infected NRK cells are to proliferate in serum-free medium. 303 73

Hormone treatment of NIH 3T3 cells that contain recombinant fusions between the mouse mammary virus long terminal repeat and the v-ras gene of Harvey murine sarcoma virus results in conditional expression of the ras p21 gene product. Levels of ras mRNA and p21 are maximal after 2 to 4 h of hormone treatment. Analysis of cellular RNA by Northern blotting and nuclease S1 protection assays indicates that the expression of two cellular RNA species increases with kinetics similar to v-ras: v-sis-related RNA and retrovirus-related VL30 RNA. Run-on transcription in isolated nuclei shows that the increase in v-sis-related RNA is not dependent on transcription and therefore must arise by a post-transcriptional mechanism. The increase in VL30 expression is a transcriptional effect. Hormone treatment of normal NIH 3T3 cells has no effect on the expression of these DNA sequences. These results suggest that v-ras stimulation of autocrine factors may play a role in transformation of cells by this gene and also suggest a reverse genetic strategy to determine the nucleic acid sequences and cellular factors involved in the regulation of gene expression that is observed.
Mol Cell Biol 1987 Jul
PMID:Rapid and selective alterations in the expression of cellular genes accompany conditional transcription of Ha-v-ras in NIH 3T3 cells. 303 49

The CD11b (Mol) molecule is a member of a family of surface glycoproteins that are essential for adhesion-dependent granulocyte functions. Brief exposure of granulocytes to human granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro increases the surface expression of CD11b and increases granulocyte adhesiveness. To assess the possible in vivo significance of these observations we studied the effect of GM-CSF on CD11b, CD11a (LFA-1), and CD11c (gp 150, 95) expression on granulocytes from nine adult patients with sarcoma who were receiving GM-CSF as part of a phase I trial. GM-CSF was administered as a continuous infusion at a dose of 32 or 64 micrograms/kg/d. Granulocyte CD11b, CD11a, and CD11c expression was determined by indirect immunofluorescence staining of whole blood, thereby minimizing in vitro manipulation. A transient leukopenia developed within 15 minutes of initiation of GM-CSF treatment that was associated with a marked increase in the surface antigen density of CD11b. A mean 1.7-fold increase (P = .001) in the percentage of CD11b-positive granulocytes and a mean 2.1-fold increase (P = .002) in CD11b surface antigen density was noted after 12 hours of treatment. No change in CD11a or CD11c expression was observed over the first 12 hours. The level of CD11b expression was followed in six patients for up to 5 days of treatment with GM-CSF. Compared with the 12-hour value, three of six patients showed a subsequent decrease in CD11b expression, two remained constant, and one showed a continued increase in CD11b surface density. Fluorescence-activated cell sorting of granulocytes into high- and low-density CD11b-positive groups revealed a preponderance of immature myeloid forms in the low-density CD11b fraction, which suggests that the late decrease in CD11b expression in some patients may be related to a greater proportion of circulating immature myeloid forms in the peripheral blood. This study suggests that GM-CSF administered as a continuous infusion rapidly upregulates the expression of granulocyte CD11b in vivo. The influence of this phenomenon on in vivo granulocyte aggregation may be clinically relevant with regard to the toxicity of GM-CSF and deserves further investigation.
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PMID:Granulocyte-macrophage colony-stimulating factor induces the expression of the CD11b surface adhesion molecule on human granulocytes in vivo. 304 45

The v-rasH oncogene of Harvey murine sarcoma virus encodes a 21,000-dalton p21 protein which has been expressed at a high level as a fusion protein in Escherichia coli. We have purified the p21 to over 90% in purity without the use of any detergent or protein denaturant. The purified p21 possesses full biochemical activities of GTP/GDP binding, autokinase, and GTPase. Scatchard analysis indicates a single class of binding sites with Kd values of 0.83 X 10(-8)M for GTP and 1.0 X 10(-8)M for GDP. The binding site can be specifically labeled with a [3H]GTP photoaffinity analog, P3-(4-azidoanilido)-5' GTP. To probe for the active center of p21, we used a battery of six monoclonal antibodies to p21 to examine their effects on p21 activities. We found that only one monoclonal antibody, Y13-259, was capable of inhibiting both GTP/GDP binding and autokinase enzymatic activities, suggesting that these p21 activities are related activities conferred by a single active center within the p21 molecule. These observations together with the recent finding that microinjection of the same monoclonal antibody into NIH 3T3 cells specifically blocks p21 in vivo function (Mulcahy et al., Nature [London] 313:241, 1985) strongly suggest that p21 in vitro activities are responsible for its cellular function.
Mol Cell Biol 1985 Jun
PMID:Biochemical properties of a highly purified v-rasH p21 protein overproduced in Escherichia coli and inhibition of its activities by a monoclonal antibody. 316 96


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