Chromosomal assignment of the human homologues of feline sarcoma virus and avian myeloblastosis virus onc genes

c-MYB and DMTF1 in Cancer

The c-Myb gene encodes a transcription factor that regulates cell proliferation, differentiation, and apoptosis through protein-protein interaction and transcriptional regulation of signaling pathways. The protein is frequently overexpressed in human leukemias, breast cancers, and other solid tumors suggesting that it is a bona fide oncogene. c-MYB is often overexpressed by translocation in human tumors with t(6;7)(q23;q34) resulting in c-MYB-TCRβ in T cell ALL, t(X;6)(p11;q23) with c-MYB-GATA1 in acute basophilic leukemia, and t(6;9)(q22-23;p23-24) with c-MYB-NF1B in adenoid cystic carcinoma. Antisense oligonucleotides to c-MYB were developed to purge bone marrow cells to eliminate tumor cells in leukemias. Recently, small molecules that inhibit c-MYB activity have been developed to disrupt its interaction with p300. The Dmp1 (cyclin D binding myb-like protein 1; Dmtf1) gene was isolated through its virtue for binding to cyclin D2. It is a transcription factor that has a Myb-like repeat for DNA binding. The Dmtf1 protein directly binds to the Arf promoter for transactivation and physically interacts with p53 to activate the p53 pathway. The gene is hemizygously deleted in 35-42% of human cancers and is associated with longer survival. The significances of aberrant expression of c-MYB and DMTF1 proteins in human cancers and their clinical significances are discussed.

Alu elements mediate MYB gene tandem duplication in human T-ALL

Recent studies have demonstrated that the MYB oncogene is frequently duplicated in human T cell acute lymphoblastic leukemia (T-ALL). We find that the human MYB locus is flanked by 257-bp Alu repeats and that the duplication is mediated somatically by homologous recombination between the flanking Alu elements on sister chromatids. Nested long-range PCR analysis indicated a low frequency of homologous recombination leading to MYB tandem duplication in the peripheral blood mononuclear cells of approximately 50% of healthy individuals, none of whom had a MYB duplication in the germline. We conclude that Alu-mediated MYB tandem duplication occurs at low frequency during normal thymocyte development and is clonally selected during the molecular pathogenesis of human T-ALL.

Inhibition of c-fes expression by an antisense oligomer causes apoptosis of HL60 cells induced to granulocytic differentiation

The c-fes protooncogene is expressed at high levels in the terminal stages of granulocytic differentiation, but so far no definite function has been attributed to the product of this oncogene. To tackle this problem, the c-fes protooncogene expression has been inhibited in HL60 cells, and fresh leukemic promyelocytes of acute promyelocytic leukemia have been induced to differentiate with retinoic acid (RA) and dimethylsulfoxide (DMSO). Inhibition was obtained by incubating the cells with a specific c-fes antisense oligodeoxynucleotide. It was observed that the cells, rather than differentiating, underwent premature cell death showing the morphological and molecular characteristics of apoptosis. This process was inhibited by granulocyte and granulocyte/macrophage colony-stimulating factor, but not by interleukin 3 (IL-3), IL-6, or stem cell factor. Our present results demonstrate that the loss of cell viability that occurs during the in vitro differentiation of myeloid cells, after the complete inhibition of the c-fes gene product and treatment with RA-DMSO, is due to activation of programmed cell death. It is concluded that a possible role of the c-fes gene product is to exert an antiapoptotic effect during granulocytic differentiation.

Chromosomal localization of the gene for a human cytosolic thyroid hormone binding protein homologous to the subunit of pyruvate kinase, subtype M2

A cDNA for the gene that encodes a human cytosolic thyroid hormone binding protein (p58) recently has been isolated and sequenced. Analysis of the p58 sequence indicates that it is identical to the subunit of pyruvate kinase, subtype M2. By in situ hybridization, the gene for p58 was mapped to 15q24-25. This localization shows that the p58 gene is not linked to the L-type of pyruvate kinase, which is located on chromosome 1. The p58 gene was found to be activated in several forms of cancer. Current localization will permit us to assess the effect of alterations involving chromosome 15 on the structure and activity of the p58 gene in neoplasms or chromosome syndromes.

Chromosomal reallocation of the chicken c-myb locus and organization of 3'-proximal coding exons

In the course of our studies concerning the tissue-specific expression of the c-myb proto-oncogene, we have established the nucleotide sequence of the chicken c-myb 3'-proximal coding exons. In situ hybridization performed with different genomic DNA probes corresponding to nearly all the c-myb gene allowed us to localize the corresponding locus on the large acrocentric chromosome 3 in chicken. Our sequencing data also indicate that the 3'-proximal noncoding sequences represented in c-myb mRNA species are derived from non-contiguous exons.

Molecular mapping of the oncogene MYB and rearrangements in malignant melanoma

The human cellular oncogene MYB has been mapped to 6q22-q23. Deletions and translocations involving this region of the long arm of chromosome 6 occur frequently in human malignant melanoma, and there are anecdotal reports of MYB gene rearrangements in this cancer. In the current study, Southern blotting and pulsed field gel electrophoresis (PFGE) have been performed to determine whether MYB or its flanking regions are commonly altered in malignant melanoma. Southern blotting failed to document obvious rearrangement of the MYB gene in 15 cases studied. To extend analysis of the MYB region, a long-range restriction map was established by PFGE. This map was then linked to the known restriction map of frequent cutting enzymes. Based on the mapping data and analysis of the MYB region in melanomas, ClaI tissue-specific variation due to methylation was demonstrated. Also, two melanomas (containing alterations in band 6q13) also demonstrated by PFGE a unique restriction fragment for the MYB gene. These results extend significantly the physical map surrounding the MYB locus and provide further evidence for the rearrangement of chromosome 6 in malignant melanoma.

The molecular genetics of human chromosome 6

Chromosome 6 contains several clinically important markers as well as classical enzyme loci, proto-oncogenes, and a growing number of anonymous DNA restriction fragment length polymorphisms (RFLPs). It is also of unique interest because of the location of the major histocompatibility complex (MHC) on the short arm, at 6p21.3. The MHC is one of the most detailed areas of the human genetic map to date and many important diseases, some of a suspected autoimmune aetiology, are associated with it.

A restriction fragment length polymorphism at the murine c-myb locus

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DNA segment containing C beta 1, a gene for the constant region of the beta chain of the T-cell antigen receptor, was inserted into chromosome 6 in cells from one patient with human T-cell leukemia

DNA rearrangements that occurred in the vicinity of T-cell antigen receptor beta-chain gene clusters residing on chromosome 7 were examined in human T-cell acute lymphoblastic leukemia cells. In one patient, it was observed that, for the T-cell receptor beta-chain genes, a D beta 1-J beta 2.3 (where D is diversity and J is joining) junction was found on one chromosome, while the other chromosome kept the germ-line configuration. If this D beta-J beta junction was formed by the customary deletion mechanism, the C beta 1 gene (where C is constant) located between the D beta 1 and J beta 2.3 loci should have disappeared from this chromosome. The C beta 1 gene indeed was absent from the rearranged chromosome 7, but it was found on chromosome 6 as an inserted segment. The implications of the observations are discussed.

The gene encoding vasoactive intestinal peptide is located on human chromosome 6p21----6qter

Vasoactive intestinal peptide (VIP) is a regulatory neuropeptide involved in a wide variety of functions, among them vasodilation, smooth muscle relaxation, sweat secretion, gastrointestinal peristalsis, and pancreatic function. A deficient VIP-innervation of sweat glands was recently described as a possible pathogenic factor in sweating of cystic fibrosis (CF) patients. To investigate a possible role for a defective VIP-gene in cystic fibrosis, we have used a panel of rodent-human hybrid cells, retaining defined complements of human chromosomes to localize the VIP-gene to the human chromosome region 6p21----6qter. As the CF gene was recently mapped to chromosome 7, we conclude that the VIP-gene is not the primary gene defect in this disease.

Human c-myb protooncogene: nucleotide sequence of cDNA and organization of the genomic locus

We have isolated cDNA clones of the human c-myb mRNA that contain approximately 3.4 kilobases of the approximately 3.8-kilobase mRNA sequence. Nucleotide sequence analysis shows that the c-myb mRNA contains an open reading frame of 1920 nucleotides, which could encode a 72-kDa protein. The cDNA nucleotide sequence and the predicted amino acid sequence of the c-myb protein are highly homologous to the corresponding chicken and mouse proteins. In particular, a region toward the NH2 terminus of the protein containing a 3-fold tandem repeat of 51 residues is evolutionarily conserved and is the only region of homology with the Drosophila c-myb protein. This region may represent a functionally important structure, most likely the DNA-binding domain. cDNA clones have been used to isolate genomic clones and to define a preliminary intron/exon organization of the c-myb gene. Identification of 5' and 3' coding and noncoding exons indicates that the human c-myb locus spans a 40-kilobase region.

Human histone genes map to multiple chromosomes

Histone genes were mapped to at least three human chromosomes by Southern blot analysis of DNAs from a series of mouse-human somatic cell hybrids (using 32P-labeled cloned human histone DNA as probes). Chromosome assignment was confirmed by in situ hybridization of radiolabeled histone gene probes (3H-labeled) to metaphase chromosomes. One human histone gene cluster (lambda HHG41) containing an H3 and H4 gene resides only on chromosome 1, whereas other clusters containing core (H3, H4, H2A, and H2B) alone (lambda HHG17) or core together with H1 histone genes (lambda HHG415) have been assigned to chromosomes 1, 6, and 12. These results suggest that the multigene family of histone coding sequences that reside in a series of clusters may be derived from a single cluster containing one each of the genes for the five principal classes of histone proteins. During the course of evolution, a set of events, probably involving reduplication, sequence modification, and recombination, resulted in the present pattern of human histone gene distribution among several chromosomes.

Acute myelogenous leukaemia with c-myc amplification and double minute chromosomes

Cytogenetic analysis of bone-marrow cells from a woman with preleukaemia showed numerous mitoses with trisomy 4 and double minute chromosomes. These abnormalities were later seen in blood cells during subsequent acute myeloid leukaemia (AML). Complete remission was achieved with three courses of doxorubicin, cytosine arabinoside, and prednisone. A further clonal abnormality, trisomy 6, was seen in leukaemic cells after the first relapse. Analyses of total DNA from the peripheral-blood cells during relapse showed that the c-myc oncogene was amplified about 30-fold in the leukaemic cells. The N-myc, c-mos, and c-myb oncogenes showed only single-copy signals. On average about two copies of c-myc resided on each dmin chromosome. The finding of amplification of a cellular oncogene (c-myc) in fresh AML cells containing double minute chromosomes suggests that clonal evolution of some leukaemia cell populations may involve selection for increased dosage of oncogenes.

Chromosome localization of the gene for human terminal deoxynucleotidyltransferase to region 10q23-q25

Complementary DNA clones representing the 3' half, the 5' half, and the entire coding region of the human terminal deoxynucleotidyltransferase gene (TdT; DNA nucleotidylexotransferase, nucleosidetriphosphate: DNA deoxynucleotidylexotransferase, EC 2.7.7.31) were used to screen a panel of mouse X human somatic cell hybrid DNAs to determine the chromosomal location of the human TdT gene. The results of the Southern transfer analysis of hybrid DNAs indicate that the gene for TdT is located on human chromosome 10. The in situ hybridization technique was then used to further localize the gene for TdT to region q23-q25 of human chromosome 10.

Nucleic acid sequence database VI: Retroviral oncogenes and cellular proto-oncogenes

The databases of the Protein Identification Resource at the National Biomedical Research Foundation (NBRF) contain nucleic acid and protein sequences from 18 retroviral oncogenes (v-onc) and 8 cellular proto-oncogenes (c-onc). Comparison of the sequences between the v-onc and c-onc genes reveals: (i) The c-src, c-abl, c-mos, c-fos, c-ras, c-myb, c-myc, and c-sis genes contain coding regions that are highly conserved in the respective v-onc genes with a small number of base changes. (ii) There are more transitions than transversions. (iii) Some of these base changes are silent mutations and others generate amino acid substitutions in the viral proteins. The causes of these base changes in the coding sequences and the significance to oncogenic transformation of the amino acid substitutions in the viral proteins remain to be determined.

Chromosomal mapping of murine c-fes and c-src genes

The murine homologs of two viral oncogenes associated with tyrosine-specific kinase activity have been assigned to different loci in the mouse genome. The segregation of restriction site polymorphisms, as detected by probes that are specific for endogenous c-fes and c-src sequences, was followed in the DNA of recombinant inbred strains. The c-fes gene was mapped to the proximal portion of chromosome 7, very close to the Gpi-1 locus, whereas c-src was linked to the Psp locus on the distal half of chromosome 2.

Some questions on the significance of chromosome alterations in leukemias and lymphomas: a review

Recent improvement in the methods of chromosome analysis has allowed recognition of consistent chromosome alterations in several human cancers, especially leukemias and lymphomas. At the same time, newly discovered human cellular oncogenes have been mapped to individual chromosomes, with precise band assignment. Some of the assignments are coincident with the breakpoints of translocations observed in particular tumors. In fact, a relocation of the corresponding oncogenes has been observed in the cells of some of these tumors. Two notable examples are that of the t(9;22) translocation of chronic myelogenous leukemia (CML), causing the transfer of the oncogene c-abl from chromosome 9 to chromosome 22, and that of the t(8;14) translocation of Burkitt lymphoma, causing the transfer of the oncogene c-myc from chromosome 8 to chromosome 14. These findings can be taken as indicative of a critical role of chromosome alterations in the origin of cancer, through the activation of one or more cellular oncogenes, although there is no firm evidence that such an activation actually occurs. In addition, some concern exists over the validity of accepting in vitro transformation of a cell line by oncogenes as a model of carcinogenesis in man. For these reasons the question on the significance of chromosome alterations in leukemias and lymphomas should not be considered entirely settled yet. Useful models, whose study may lead to the clarification of this important point, are represented by premalignant conditions, such as the myeloproliferative disorders, where chromosome abnormalities are present before the development of a bona fide neoplasm, and by the aneuploidy syndromes, in which there exists an association between a constitutional chromosome anomaly and an increased risk of cancer.

Chromosomal mapping of murine c-fes and c-src genes

The murine homologs of two viral oncogenes associated with tyrosine-specific kinase activity have been assigned to different loci in the mouse genome. The segregation of restriction site polymorphisms, as detected by probes that are specific for endogenous c-fes and c-src sequences, was followed in the DNA of recombinant inbred strains. The c-fes gene was mapped to the proximal portion of chromosome 7, very close to the Gpi-1 locus, whereas c-src was linked to the Psp locus on the distal half of chromosome 2.

Regional assignment of human protooncogene c-myb to 6q21----qter

Using human-mouse somatic cell hybrids containing different parts of chromosome 6 and a DNA probe of the oncogene (v-myb) of avian myeloblastosis virus (AMV), we regionally mapped by Southern blot techniques the human cellular myb (c-myb) protooncogene to 6q21----qter.

Oncogenes: clues to carcinogenesis

Recent applications of recombinant DNA techniques in cancer research led to the detection of cellular genes with potential transforming activity, called oncogenes (c-onc). Regularly they seem to be involved in normal cell differentiation and proliferation: a number of oncogene-encoded proteins specifically phosphorylates tyrosine, a key reaction in growth control. Certain human tumors exhibit activated forms of these genes and DNA fragments isolated from these neoplasms transform nonneoplastic cells (transfection assay). Oncogenes were first discovered and defined in a number of retroviruses; these viral oncogenes (v-onc) are thought to have been derived from the cellular oncogenes (c-onc). By integration of the v-onc genes into the host genome acute neoplastic transformation of the cell may occur. Several modes of oncogene activation are discussed that lead either to an increased dosage of gene product or to the formation of an altered gene product. The localization of oncogenes in the human genome near the breakpoints of specific chromosome aberrations involved in various neoplasms like Burkitt lymphoma and several leukemias emphasizes the importance of these genes in carcinogenesis.

RNA-tumorviruses, oncogenes, and their possible role in human carcinogenesis

The detection and characterization of oncogenes via RNA tumor viruses (or retroviruses) and the recognition of their location at breakpoints of chromosomal translocations which are frequently found in certain human neoplasms has promoted present understanding of molecular mechanisms underlying carcinogenesis. Oncogenes are cellular genes which can be transduced by RNA tumorviruses and induce malignant transformation under experimental conditions in vivo and in vitro. A role of retroviruses in human leukemogenesis is suggested by epidemiological observations and by the isolation of such viruses from several human T-cell leukemias and lymphomas (human T-cell leukemia/lymphoma virus or HTLV) as well as by biochemical association of retroviral markers with human leukemias. A role of HTLV has been suggested also in a human immune deficiency syndrome (AIDS). In view of the well known role of many factors in carcinogenesis the concept of carcinogenesis as a multistep process as well as the concept of cocarcinogenesis and the role of cofactors other than viruses, such as radiation and chemicals, aging, hormones, graft vs host reaction, environmental factors etc., will have to be carefully considered.

Regional chromosomal localization of N-ras, K-ras-1, K-ras-2 and myb oncogenes in human cells

The identification of transforming genes in human tumor cells has been made possible by DNA mediated gene transfer techniques. To date, it has been possible to show that most of these transforming genes are activated cellular analogues of the ras oncogene family. To better understand the relationship between these oncogenes and other human genes, we have determined their chromosomal localization by analyzing human rodent somatic cell hybrids with molecularly cloned human proto-oncogene probes. It was possible to assign N-ras to chromosome 1 and regionally localize c-K-ras-1 and c-K-ras-2 to human chromosomes 6pter-q13 and 12q, respectively. These results along with previous studies demonstrate the highly dispersed nature of ras genes in the human genome. Previous reports indicated that the c-myb gene also resides on chromosome 6. It has been possible to sublocalize c-myb to the long arm of chromosome 6 (q15-q21). The non-random aberrations in chromosomes 1, 6 and 12 that occur in certain human tumors suggest possible etiologic involvement of ras and/or myb oncogenes in such tumors.

Structural organization and expression of human DNA sequences related to the transforming gene of avian myeloblastosis virus

Bacteriophage libraries of human DNA were screened for sequences homologous to the transforming gene (v-myb) of avian myeloblastosis virus. The three overlapping clones isolated were shown to contain a total of 1.0 kilobase pair (kbp) of sequence related to v-myb distributed over 6.2 kbp. Restriction enzyme mapping and heteroduplex analysis revealed the presence of five myb-related domains interrupted by four stretches of non-homology. To study the extent of human DNA coding sequences that constitute the myb gene homologue, c-myb (human), probes spanning about 30 kbp were prepared from the clones and used to study transcription in a human hematopoietic cell line (MOLT-4). Each of the probes hybridized a 4.5-kilobase transcript, which suggests that either the c-myb (human) gene encompasses 30 kbp or it contains two or more transcription units that each give rise to a mRNA of 4.5 kilobases.

A familial reciprocal translocation t(3;7) (p21.1;p13) associated with the Greig polysyndactyly-craniofacial anomalies syndrome

A translocation t(3;7) (p21.l;p13) segregating through four generations was found to be invariably associated with the Greig cephalopolysyndactyly syndrome (GS). High resolution chromosome analyses using G and R banding did not uncover any imbalance of the affected chromosomes, nor were the late replicating patterns changed. One girl with the GS died of medulloblastoma.

The tumor phenotype and the human gene map

The tumor phenotype is associated with the rearrangement of genetic information and the altered expression of many gene products. In this review, genes associated with the tumor phenotype have been arranged on the human gene map and indicate the extent to which the tumor phenotype involves the human genome. Nonrandom chromosomal aberrations that are frequently observed in tumors are presented. Altered metabolic demands of the tumor cell are reflected in altered gene expressions of a wide range of enzymes and other proteins, and these changed enzyme patterns are described. The study of oncogenes increasingly suggests that they may be significant in certain cancers, and the assignment of these genes has been tabulated. The biochemical and metabolic changes observed in tumors are complex; studying the patterns and interactions of these changes will aid our genetic understanding of the origins and development of tumors.

Chromosomal localization of the human c-fms oncogene

A molecular probe was prepared with specificity for the human cellular homologue of transforming sequences represented within the McDonough strain of feline sarcoma virus (v-fms). By analysis of a series of mouse-human somatic cell hybrids containing variable complements of human chromosomes it was possible to assign this human oncogene, designated c-fms, to chromosome 5. Regional localization of c-fms to band q34 on chromosome 5 was accomplished by analysis of Chinese hamster-human cell hybrids containing as their only human components, terminal and interstitial deleted forms of chromosome 5. The localization of c-fms to chromosome 5 (q34) is of interest in view of reports of a specific, apparently interstitial, deletion involving approximately two thirds of the q arm of chromosome 5 in acute myelogenous leukemia cells.

The N-ras oncogene assigned to the short arm of human chromosome 1

The human N-ras oncogene, isolated from the HL-60 promyelocytic leukemia cell line, is distantly related to viral oncogenes of Kirsten and Harvey sarcoma viruses. We have determined its chromosomal location by Southern blot analysis of DNAs from 37 human x rodent hybrid cell lines derived from 8 different human donors, some of whom carried balanced rearrangements of chromosome 1. The results indicate that the N-ras oncogene (RASN) is localized on the proximal part of the short arm of human chromosome 1, in region p3200 leads to cen.

Genetic analysis of the 15;17 chromosome translocation associated with acute promyelocytic leukemia

Somatic cell hybrids have been constructed between a thymidine kinase-deficient mouse cell line and blood leukocytes from a patient with acute promyelocytic leukemia showing the 15q+;17q- chromosome translocation frequently associated with this disease. One hybrid contains the 15q+ translocation chromosome and very little other human material. We have shown that the c-fes oncogene, which has been mapped to chromosome 15, is not present in this hybrid and, therefore, probably is translocated to the 17q- chromosome. Analysis of the genetic markers present in this hybrid has enabled a more precise localization of the translocation breakpoints on chromosomes 15 and 17. Our experiments also have enabled an ordering and more precise mapping of several genetic markers on chromosomes 15 and 17.

Differential expression of the normal and of the translocated human c-myc oncogenes in B cells

We have investigated whether the translocated and the untranslocated human c-myc oncogenes of Burkitt lymphoma cells are equally or differentially expressed in host mouse B cells. The human c-myc mRNA levels in somatic cell hybrids between mouse plasmacytoma cells and Burkitt lymphoma cells with either the t(8;14) or the t(2;8) chromosome translocation were determined by using the nuclease S1 protection procedure. Although both the human parental lines and the hybrid cells carrying the translocated c-muc oncogene expressed high levels of human specific c-myc transcripts, the hybrid cells carrying the untranslocated c-myc gene on normal chromosome 8 did not contain human specific c-myc mRNA. These results suggest that the translocated human c-myc oncogene has escaped the normal transcriptional control to which the untranslocated c-myc gene remains subjected. This interpretation is also supported by the finding that the expression of the c-myc genes of lymphoblastoid cells and of HL-60 promyelocytic leukemia cells are repressed when they are transferred into a mouse plasmacytoma background. The ability of the translocated c-myc oncogene to escape the normal transcriptional control occurring in B cells may be important for the expression of B cell neoplasia in mouse and man. We have also transferred the Burkitt 14q+ chromosome carrying a translocated c-myc oncogene into mouse LM-TK- fibroblasts and studied the levels of human c-myc transcripts in the hybrids. Because the levels of human c-myc transcripts in the fibroblast hybrids are dramatically decreased in comparison to the plasmacytoma hybrids, we conclude that the levels of transcripts of the translocated c-myc oncogene depend on the differentiated state of the cells harboring the translocated chromosome.

The chromosomal basis of human neoplasia

High-resolution banding techniques for the study of human chromosomes have revealed that the malignant cells of most tumors analyzed have characteristic chromosomal defects. Translocations of the same chromosome segments with precise breakpoints occur in many leukemias and lymphomas, and a specific chromosome band is deleted in several carcinomas. Trisomy, or the occurrence of a particular chromosome in triplicate, is the only abnormality observed in a few neoplasias. It is proposed that chromosomal rearrangements play a central role in human neoplasia and may exert their effects through related genomic mechanisms. Thus, a translocation could serve to place an oncogene next to an activating DNA sequence, a deletion to eliminate an oncogene repressor, and trisomy to carry extra gene dosage.

Chromosomal sublocalization of human c-myb and c-fes cellular onc genes

The transforming genes of acutely transforming retroviruses are derived from conserved cellular genes (c-onc genes) which are believed to be important in normal cell growth and differentiation. Recent studies indicate that altered expression of c-onc genes, for example, by insertion of viral genomes, gene amplification or chromosomal translocation, can lead to development of malignant diseases in man and animals. c-myb and c-fes are homologues of the transforming genes of avian myeloblastosis virus and feline sarcoma virus (Gardner and Snyder-Theilen strains), respectively. c-myb is transcribed preferentially in immature haematopoietic cells and probably codes for a protein important in differentiation of these cells. The viral fes gene, like several other viral onc genes, encodes a tyrosine-specific protein kinase. However, c-fes transcripts have not been detected in the types of human cells examined so far. c-myb and c-fes have been assigned to human chromosomes 6 and 15, respectively. Specific aberrations involving these chromosomes have been observed at high frequency in several human neoplasms. We have now sublocalized c-myb to 6q22-24 and c-fes to 15q25-26 by in situ hybridization of the human c-onc probes to human mitotic chromosome preparations. These chromosomal segments are indeed involved in nonrandom translocations in several human tumours. The results encourage further investigation into the role of onc genes in the pathogenesis of specific neoplasms.

Homology between phosphotyrosine acceptor site of human c-abl and viral oncogene products

The human homologues of several independent viral oncogenes, each of which encodes tyrosine-specific protein kinases, have been identified. Of these, three (v-src, v-yes and v-fes/fps) are known to exhibit considerable sequence homology, particularly in the regions of their phosphorylation acceptor sites. In the present study, sequences encoding the tyrosine phosphorylation acceptor sites of the Abelson murine leukaemia virus oncogene, v-abl, and its human cellular homologue, c-abl, have been identified and their nucleic acid sequences determined. Our results establish extensive homology between this region of c-abl and acceptor domains of the v-src, v-yes and v-fes/fps family of viral oncogenes, as well as more distant relatedness to the catalytic chain of the mammalian cyclic AMP-dependent protein kinase. These findings suggest that, of the homologues of retroviral oncogenes with tyrosine protein kinase activity examined to date, all were probably derived from a common progenitor and may represent members of a diverse family of cellular protein kinases.

Structure and biological activity of v-raf, a unique oncogene transduced by a retrovirus

We have molecularly cloned a unique acutely transforming replication-defective mouse type C virus (3611-MSV) and characterized its acquired oncogene. The viral genome closely resembles Moloney (M) murine leukemia virus (MuLV), except for a substitution in M-MuLV in the middle of p30 and the middle of the polymerase gene (pol). Heteroduplex analysis revealed that 2.4 kilobases of M-MuLV DNA were replaced by 1.2 kilobases of cellular DNA. The junctions between viral and cellular sequences were determined by DNA sequence analysis to be 517 nucleotides into the p30 sequence and 1,920 nucleotides into the polymerase sequence. Comparison of the transforming gene from 3611-MSV, designated v-raf, with previously isolated retrovirus oncogenes either by direct hybridization or by comparison of restriction fragments of their cellular homologs shows it to be unique. Transfection of NIH 3T3 cells with cloned 3611-MSV proviral DNA leads to highly efficient transformation and the recovered virus elicits tumors in mice typical of the 3611-MSV virus. Transfected NIH 3T3 cells express two 3611-MSV-specific polyproteins (P75 and P90), both of which contain NH2-terminal gag gene-encoded components linked to the acquired sequence (v-raf) translational product. The cellular homolog, c-raf, is present in one or two copies per haploid genome in mouse and human DNA.

c-sis is translocated from chromosome 22 to chromosome 9 in chronic myelocytic leukemia

By analysis of a series of somatic cell hybrids derived by fusion of either mouse or Chinese hamster cells with leukocytes from different chronic myelocytic leukemia (CML) patients or from normal donors, we have localized the human oncogene, c-sis, on the q11 to qter segment of chromosome 22 and demonstrated its translocation from chromosome 22 to chromosome 9 (q34) in CML.

Chromosomal assignment of a family of human oncogenes

A family of human transforming genes, previously shown to share homology with the ras family of viral oncogenes, maps to three different human chromosomes. A well-characterized mouse-human hybrid cell panel, combined with Southern blotting, was used in this study. The transforming gene of the T24 bladder carcinoma cell line maps to human chromosome 11. An oncogene isolated from the lung carcinoma cell line SK-Calu-1 maps to human chromosome 12. The third ras-related gene, cloned from SK-N-SH, a neuroblastoma cell line, maps to human chromosome 1.

Mapping of an endogenous retroviral sequence to human chromosome 18

The application of recombinant DNA technologies has allowed the detection of at least three families of moderately repetitive DNA segments in the human genome that are homologous to retroviruses previously isolated from mice and primates. One of these DNA segments has been shown by nucleotide sequence comparisons to be distantly related to both Moloney murine leukaemia virus (MoMuLV) and the endogenous baboon retrovirus and to have the sequence organization characteristic of an integrated retrovirus. Isolation of the homologous locus from chimpanzee DNA indicated that the integration event preceded the evolutionary divergence of chimpanzees and man. Here we have used a panel of rodent x human somatic cell hybrids to assign the chromosomal localization of this segment, called ERV1 (endogenous retrovirus-1), to human chromosome 18 (HSA 18).

Human and mouse cellular myc protooncogenes reside on chromosomes involved in numerical and structural aberrations in cancer

A molecular clone of viral myc (v-myc), the oncogene of avian myelocytomatosis virus, MC29, detected homologous human, mouse, and Chinese hamster cellular myc (c-myc) sequences by Southern filter hybridization. A v-myc probe, containing sequences from the 3' domain of the gene, hybridized to single human HindIII and mouse EcoRI genomic DNA fragments of the cellular myc genes whose segregation could be followed in interspecies somatic cell hybrids. Human c-myc segregated concordantly with the enzyme marker glutathione reductase and with a karyotypically normal chromosome 8. A rearrangement of human c-myc was observed in Burkitt's lymphoma cells possessing the t(8;14) translocation. These results suggest that human c-myc is located close to the breakpoint on chromosome 8 (q24) involved in the t(8;14) translocation. The mouse c-myc gene segregated concordantly with chromosome 15 in mouse-Chinese hamster cell hybrids. These gene assignments are noteworthy, as structural and numerical abnormalities of human chromosome 8 and mouse chromosome 15 are associated frequently with B-cell neoplasms.