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M Goldfarb

Publications and source records attributed to M Goldfarb.

At least 73 records · Page 4Linked to original sources
PubMed1985

Functional homology of mammalian and yeast RAS genes.

Yeast spores lacking endogenous RAS genes will not germinate. If such spores contain chimeric mammalian/yeast RAS genes or even the mammalian H-ras gene under the control of the galactose-inducible GAL10 promoter, they will germinate in the presence of galactose and produce viable haploid progeny dependent on galactose for continued growth and viability. These results indicate that the biochemical function of RAS proteins is essential for vegetative haploid yeast and that this function has been conserved in evolution since the progenitors of yeast and mammals diverged.

Animals↗
PubMed1985

Purification and characterization of human H-ras proteins expressed in Escherichia coli.

The full-length normal and T24 mutant human H-ras proteins and two truncated derivatives of the T24 mutant were expressed efficiently in Escherichia coli. The proteins accumulated to 1 to 5% of total cellular protein, and each was specifically recognized by anti-ras monoclonal antibodies. The two full-length proteins as well as a carboxyl-terminal truncated derivative (deleted for 23 amino acid residues) were soluble upon cell lysis and were purified to 90% homogeneity without the use of denaturants. In contrast, an amino-terminal truncated ras derivative (deleted for 22 amino acid residues) required treatment with urea for its solubilization. The guanine nucleotide binding activity of these four proteins was assessed by a combination of ligand binding on proteins blots, immunoprecipitation, and standard filter binding procedures. The full-length proteins showed similar binding kinetics and a stoichiometry approaching 1 mol of GTP bound per mol of protein. The showed similar binding kinetics and a stoichiometry approaching 1 mol of GTP bound per mol of protein. The carboxyl-terminal truncated protein also bound GTP, but to a reduced extent, whereas the amino-terminal truncated protein did not have binding activity. Apparently, the carboxyl-terminal domain of ras, although important for transforming function, does not play a critical role in GTP binding.

DNA, Recombinant↗
PubMed1984

Genes in S. cerevisiae encoding proteins with domains homologous to the mammalian ras proteins.

The ras genes, which were first identified by their presence in RNA tumor viruses and which belong to a highly conserved gene family in vertebrates, have two close homologs in yeast, detectable by Southern blotting. We have cloned both genes (RAS1 and RAS2) from plasmid libraries and determined the complete nucleotide sequence of their coding regions. They encode proteins with nearly 90% homology to the first 80 positions of the mammalian ras proteins, and nearly 50% homology to the next 80 amino acids. Yeast RAS1 and RAS2 proteins are more homologous to each other, with about 90% homology for the first 180 positions. After this, at nearly the same position that the mammalian ras proteins begin to diverge from each other, the two yeast ras proteins diverge radically. The yeast ras proteins, like the proteins encoded by the mammalian genes, terminate with the sequence cysAAX, where A is an aliphatic amino acid. Thus the yeast ras proteins have the same overall structure and interrelationship as the family of mammalian ras proteins. The domains of divergence may correspond to functional domains of the ras proteins. Monoclonal antibody directed against mammalian ras proteins immunoprecipitates protein in yeast cells containing high copy numbers of the yeast RAS2 gene.

Amino Acid Sequence↗
PubMed1983

Structure and activation of the human N-ras gene.

The normal human N-ras gene has been cloned. In structure and sequence it closely resembles the human H-ras and K-ras genes. The three genes share regions of nucleotide homology and nucleotide divergence within coding sequences and have a common intron/exon structure, indicating that they have evolved from a similarly spliced ancestral gene. The N-ras gene of SK-N-SH neuroblastoma cells has transforming activity, while the normal N-ras gene does not, the result of a single nucleotide change substituting lysine for glutamine in position 61 of the N-ras gene product. From previous studies we conclude that amino acid substitutions in two distinct regions can activate the transforming potential of ras gene products.

Amino Acid Sequence↗
PubMed1983

Isolation and preliminary characterization of the transforming gene of a human neuroblastoma cell line.

DNA from the human neuroblastoma cell line SK-N-SH is capable of inducing foci of transformed NIH 3T3 cells after DNA-mediated gene transfer. Using genetic selection with the Escherichia coli sup F gene, we have isolated human sequences from mouse cells responsible for the oncogenic transformation. These sequences are present in all human DNAs surveyed and no gross rearrangements of these sequences are found in SK-N-SH cells. Although clearly distinct from two other human transforming genes present in bladder, lung, and colon carcinoma cell lines, all three transforming gene sequences may be related members of the ras gene family.

Animals↗
PubMed1983

Three human transforming genes are related to the viral ras oncogenes.

Three distinct transforming genes present in human tumor cell lines are all related to the viral oncogenes of Harvey and Kirsten murine sarcoma viruses, designated v-H-ras and v-K-ras, respectively. The transforming gene of a bladder carcinoma cell line has been shown to be a human homolog to v-H-ras [Parada, L. F., Tabin, C. J., Shih, C. & Weinberg, R. A. (1982) Nature (London) 297, 474-478; Santos, E., Tronick, S. R., Aaronson, S. A., Pulciani, S. & Barbacid, M. (1982) Nature (London) 298, 343-347]. The transforming gene common to one colon (SK-CO-1) and two lung carcinoma (SK-LU-1 and Calu-1) cell lines is the same human homolog of v-K-ras as is the transforming gene previously identified in a lung carcinoma cell line Lx-1 [Der, C. J., Krontiris, T. G. & Cooper, G. M. (1982) Proc. Natl. Acad. Sci. USA 79, 3637-3640]. The transforming gene of SK-N-SH neuroblastoma cells is weakly homologous to both v-H-ras and v-K-ras. NIH 3T3 cells transformed with the SK-N-SH transforming gene contain increased levels of a protein serologically and structurally related to the protein products of the v-H-ras and v-K-ras genes. Therefore, it represents a third member of the ras gene family, which we have called N-ras. Based on the homology with the v-ras genes, we have established the orientation of transcription and approximate coding regions of the cloned human K-ras and N-ras genes.

Animals↗
PubMed1983

Sequence and structure of the coding region of the human H-ras-1 gene from T24 bladder carcinoma cells.

We have molecularly cloned and sequenced cDNA to the transcript of H-ras-1, the transforming gene of the T24 human bladder carcinoma cell line. The transcript derives from at least five exons in the H-ras-1 gene, and RNA splicing occurs at sites typical of exon-intron junctions. T24 H-ras-1 RNA has an AUG-initiated open reading frame of 567 nucleotides, which can encode a protein of mass comparable to the apparent molecular weight of the T24 H-ras-1 gene product. The T24 H-ras-1 gene product is nearly identical to v-H-ras p21, the transforming protein encoded by the genome of Harvey sarcoma virus. We discuss the implications of this sequence conservation in the structure-function relationships of ras proteins.

Base Sequence↗
PubMed1983

A test of the role of two oncogenes in inherited predisposition to colon cancer.

Inheritance of mutationally altered oncogenes could predispose individuals to the development of specific tumors and account for familial tumor phenotypes. Using adjacent DNA sequence polymorphisms as genetic markers, we have examined two oncogenes, the Kirsten ras2, isolated from a human colon cancer cell line, and the Harvey ras1, isolated from a human bladder cancer cell line, for their role in the genetic etiology of inherited colon cancer in Gardner syndrome. Both oncogene loci have been shown to be unlinked to the Gardner syndrome locus and are, therefore, eliminated as candidates for the Gardner syndrome gene.

Base Sequence↗
PubMed1982

Activation of the T24 bladder carcinoma transforming gene is linked to a single amino acid change.

Several different transforming genes have been observed in the DNA of a variety of tumours and tumour cell lines of human and rodent origin by the ability of these genes to induce morphological transformation in NIH 3T3 cells1-5. The transforming gene found in a human bladder carcinoma cell line, T24, is H-ras-1, the human homologue of the Harvey sarcoma virus oncogene (v-H-ras)6-9. In the present study we have compared the H-ras-1 genes cloned from T24 and normal human DNA. The H-ras-1 gene cloned from T24 DNA induces transformation in NIH 3T3 cells, while the same gene cloned from normal cellular DNA does not. The functionally significant difference between the transforming and normal genes appears to be a single base mutation, which produces an amino acid change in the sequence of the proteins that the genes encode.

Amino Acid Sequence↗
PubMed1982

Isolation and preliminary characterization of a human transforming gene from T24 bladder carcinoma cells.

DNA from T24, a cell line derived from a human bladder carcinoma, can induce the morphological transformation of NIH 3T3 cells. Using techniques of gene rescue to clone the gene responsible for this transformation, we have found that it is human in origin, less than 5 kilobase pairs in size and is homologous to a 1,100-base polyadenylated RNA species found in T24 and HeLa cells. Blot analysis indicates extensive restriction endonuclease polymorphism near this gene, in human DNAs.

Animals↗
PubMed1981

Human-tumor-derived cell lines contain common and different transforming genes.

We have screened different cultured cell lines established from human tumors for the ability of their DNAs to induce transformed foci in NIH/3T3 cells. Based on restriction endonuclease digestions and the presence of human sequences in mouse transformants, we conclude that five of these human tumor cell lines contain a gene or genes capable of transforming mouse cells and that at least three different transforming genes are present in these five lines. Three cell lines, two derived from lung carcinomas and one derived from a colon carcinoma, transfer the same or closely related human genes. If these transforming genes are mediating the tumorigenic state of the human cells, then our results indicate that overlapping pathways leading to tumorigenesis may arise independently.

3T3 Cells↗
PubMed1981

Management of paralytic ectropion.

Details of a surgical technique for permanent correction of paralytic ectropion are presented. The method has been successfully used in six patients over the past two years, all of whom improved. We feel that this is the procedure of choice in long standing paralytic ectropion.

Ectropion↗
PubMed1980

Behavior of the multiproduct firm. A model of the nonprofit hospital system.

This article presents a hospital model that recognizes the multiproduct nature of hospital output and incorporates trade-offs among various competing goals. A utility function for the hospital is defined over quantity, quality and the net revenues associated with the treatments produced. Utility is constrained by epidemiological factors and by availability of beds. The model is used to draw comparative statics implications, from which econometric hypotheses are developed and tested. This is accomplished by a set of equations that predict variations in patient-specific lengths of stay, admissions, expenses per admission, and occupancy rates. Empirical results are generally consistent with predictions. The model has a variety of policy applications, and these are illustrated.

Bed Occupancy↗