scholarly journals Expression of the c-raf protooncogene in human hematopoietic cells and cell lines

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1437-1440 ◽  
Author(s):  
E Sariban ◽  
T Mitchell ◽  
D Kufe

Abstract The murine sarcoma virus 3611 contains the transforming v-raf gene that has partial nucleotide homology with the src family of tyrosine kinase- encoding oncogenes. Although this virus induces fibrosarcomas in mice, a recombinant murine retrovirus carrying both the raf and myc oncogenes induces immunoblastic lymphomas and immortalizes mouse macrophages in vitro. The present study has thus monitored the expression of c-raf in human hematopoietic cells. The results demonstrate the presence of a 3.6-kb c-raf transcript in HL-60 promyelocytic leukemic cells. The induction of HL-60 cell differentiation along the monocytic or granulocytic lineages had no detectable effect on the level of c-raf transcripts. Furthermore, in contrast to c-myc and c-fms expression, inhibition of protein synthesis with cycloheximide had no detectable effect on c-raf expression. Similar levels of c-rafRNA were also found in other human cell lines derived from myeloid, B cell, and T cell tumors, as well as in normal granulocytes, monocytes, and macrophages. These findings suggest that the c-raf protooncogene is widely expressed in multiple hematopoietic lineages.

Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1437-1440
Author(s):  
E Sariban ◽  
T Mitchell ◽  
D Kufe

The murine sarcoma virus 3611 contains the transforming v-raf gene that has partial nucleotide homology with the src family of tyrosine kinase- encoding oncogenes. Although this virus induces fibrosarcomas in mice, a recombinant murine retrovirus carrying both the raf and myc oncogenes induces immunoblastic lymphomas and immortalizes mouse macrophages in vitro. The present study has thus monitored the expression of c-raf in human hematopoietic cells. The results demonstrate the presence of a 3.6-kb c-raf transcript in HL-60 promyelocytic leukemic cells. The induction of HL-60 cell differentiation along the monocytic or granulocytic lineages had no detectable effect on the level of c-raf transcripts. Furthermore, in contrast to c-myc and c-fms expression, inhibition of protein synthesis with cycloheximide had no detectable effect on c-raf expression. Similar levels of c-rafRNA were also found in other human cell lines derived from myeloid, B cell, and T cell tumors, as well as in normal granulocytes, monocytes, and macrophages. These findings suggest that the c-raf protooncogene is widely expressed in multiple hematopoietic lineages.


1982 ◽  
Vol 2 (1) ◽  
pp. 42-51
Author(s):  
S Gattoni ◽  
P Kirschmeier ◽  
I B Weinstein ◽  
J Escobedo ◽  
D Dina

Moloney murine sarcoma virus carries an oncogenic sequence (v-mos) which is homologous to a single copy gene (c-mos) present in the normal cells of several vertebrate species. Because of the possible significance of c-mos sequences in normal development and malignant transformation induced by physical or chemical agents, we have examined the state of integration, methylation, and transcriptional activity of c-mos sequences in a variety of normal rodent tissues, normal cell lines, or cell lines transformed by radiation or chemical carcinogens. DNA-DNA hybridization, utilizing the Southern blotting technique and a plasmid-derived DNA probe representing the v-mos sequence, gave no evidence for rearrangements of the c-mos sequence in the DNAs obtained from these diverse cell types. Parallel studies employing the restriction enzyme isoschizomers HpaII and MspI indicated that in all of these cell types the c-mos sequences were heavily methylated. In addition, analysis of cellular RNAs by blot hybridization with the v-mos probe failed to detect evidence of transcription of the c-mos sequences in any of these cell types. This was in contrast to a Moloney sarcoma virus-transformed cell line in which we found that the integrated v-mos sequence was both undermethylated and extensively transcribed. Thus, it would appear that c-mos sequences do not play a role in the transformation of rodent cells by chemical or physical agents, although the possible role of other endogenous onc sequences remains to be determined.


1982 ◽  
Vol 2 (11) ◽  
pp. 1339-1345
Author(s):  
R W Ellis ◽  
D DeFeo ◽  
M E Furth ◽  
E M Scolnick

The Kirsten (Ki) and Harvey (Ha) strains of murine sarcoma virus encode a 21,000-dalton protein (p21 ras) which is the product of the transforming gene of these viruses. Normal cells express low levels of p21 ras encoded by cellular genes (Ki-ras and Ha-ras) homologous to the Ki and Ha murine sarcoma virus transformation genes. A bone marrow-derived mouse cell line, 416B, has been shown to express unusually high levels of p21 ras. In this manuscript, we investigated the molecular biology of p21 ras gene expression in 416B and other normal mouse cells. We identified four distinct polyadenylated and polysome-associated RNAs, two related to Ki-ras and two to Ha-ras. The levels in 416B cells of the two Ki-ras RNAs, sized 5.2 and 2.0 kilobases, were both elevated approximately 25-fold over levels found in normal mouse cells; there was no corresponding change in 416B cells in the levels of the two Ha-ras RNAs. We partially purified the two Ki-ras mRNAs and separated them by velocity sedimentation in sucrose density gradients. Both the 5.2- and 2.0-kilobase mRNAs could be translated in vitro into p21 ras. These results show that a cellular onc protein can be translated from two distinct cellular mRNA species.


1973 ◽  
Vol 59 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Keith R. Porter ◽  
George J. Todaro ◽  
Virginia Fonte

Cells of the mouse line Balb/3T3 as well as three virus-induced transformants and two spontaneous transformants grown in vitro have been studied for their topography by scanning electron microscopy. The parent cell in confluent culture closely resembles an endothelial cell in its form and in the structure of its association with adjacent cells. The tumorigenic transformants produced by SV40, murine sarcoma virus, or polyoma viruses are fusiform to pleomorphic and distinctly different from the cell of origin. They show relatively smooth surfaces except for blebs and marginal microvilli. Perhaps most surprising is the similarity they bear to one another. This is made the more singular by the very different form shown by the tumorigenic transformants of spontaneous origin. One of these, S2-4, possesses a thickened rather than the lamellar form of the parent A31 cell and is covered by long microvilli and many spherical blebs. The other, TuT3, more closely resembles the cell of origin but shows extensive ruffling at its margins. All transformants grow without evidence of contact inhibition. The significance of the surface morphologies and the factors influencing cell form are discussed.


1984 ◽  
Vol 65 (11) ◽  
pp. 1955-1961 ◽  
Author(s):  
M. Ferrentino ◽  
P. P. Di Fiore ◽  
A. Fusco ◽  
G. Colletta ◽  
A. Pinto ◽  
...  

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