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Biomedical subjects

J Groffen

Publications and source records attributed to J Groffen.

At least 109 records · Page 6Linked to original sources
PubMed1990

DNA haplotype analyses of patients with hyperphenylalaninemia.

Linkage analysis of phenylketonurics has shown a strong association between the DNA haplotype at the phenylalanine hydroxylase (PAH) locus and phenylketonuria (PKU). Similarly, a genetic linkage between less severe forms of hyperphenylalaninemia (HPA) and the PAH locus has been suggested. In the present study we analyzed this linkage in more detail. Haplotypes at the PAH locus were determined for 19 individuals with moderately elevated plasma phenylalanine and normal urinary neopterin/biopterin ratios. Fourteen of these individuals had plasma phenylalanine levels of 4-10 mg/dl (mild HPA), and the other five had plasma phenylalanine levels of 10-19 mg/dl (atypical PKU). Thirteen of the 15 HPA families consisted of an affected child and at least one other sibling. Elevated plasma phenylalanine was seen to genetically segregate with specific PAH alleles in each family. Summation of the LOD scores for both categories of moderate plasma phenylalanine elevation gave a maximum value of 3.556 at theta = 0. At theta = 0 this gives a probability of linkage between the PAH locus and the locus for moderate phenylalanine elevations that is approximately 3,600:1. None of the alleles segregating with either mild HPA or atypical PKU were of haplotype 2 or 3, and 13/20 were of types 1 or 4. This is in agreement with the most deleterious mutations being on haplotypes 2 and 3 and with the less severe mutations being on haplotypes 1 and 4. chi 2 Analyses indicated no statistically significant correlation between HPA and a particular haplotype or restriction-enzyme site.

Alleles↗
PubMed1989

ABR, an active BCR-related gene.

The human BCR gene on chromosome 22 is specifically involved in the Philadelphia translocation, t(9;22), a chromosomal rearrangement present in the leukemic cells of patients with chronic myeloid leukemia or acute lymphoblastic leukemia. In most cases, the breakpoints on chromosome 22 are found within a 5.8 kb region of DNA designated the major breakpoint cluster region (Mbcr) of the BCR gene. Hybridization experiments have indicated that the human genome contains BCR gene-related sequences. Here we report the molecular cloning of one of these loci, for which we propose the name ABR. In contrast with the other BCR-related genes studied to date, ABR represents a functionally active gene and contains exons very similar to those found within the Mbcr. Unlike the BCR gene, the ABR gene exhibits great genomic variability caused by two different variable tandem repeat regions located in two introns. All other BCR gene-related sequences isolated so far and the BCR gene itself are located on chromosome 22. In contrast, the ABR gene is located on chromosome 17p.

Amino Acid Sequence↗
PubMed1989

Nucleotide sequence of both reciprocal translocation junction regions in a patient with Ph positive acute lymphoblastic leukaemia, with a breakpoint within the first intron of the BCR gene.

Breakpoints on chromosome 22 in the translocation t(9;22) found in Philadelphia positive acute lymphoblastic leukaemia patients fall within two categories. In the first the breakpoint is localized within the breakpoint cluster region of the BCR gene, analogous to the chromosome 22 breakpoint in chronic myeloid leukaemia. The second category has a breakpoint 5' of this area, but still within the BCR gene. We have previously shown that these breakpoints occur within the first intron of the BCR gene and cloned the 9q+ junction from such a patient. We have now determined the sequences around the breakpoints on both translocation partners from this patient as well as the germline regions. The chromosome 9 ABL sequence around the breakpoint shows homology to the consensus Alu sequence whereas the chromosome 22 BCR sequence does not. At the junction there is a 6 bp duplication of the chromosome 22 sequence which is present both in the 9q+ and in the 22q- translocation products. Possible mechanisms for the generation of the translocation are discussed.

Base Sequence↗
PubMed1989

The FER gene is evolutionarily conserved and encodes a widely expressed member of the FPS/FES protein-tyrosine kinase family.

We have recently isolated human and rat cDNAs (designated FER and flk, respectively) which encode nonreceptor protein-tyrosine kinases which are very similar to one another and related in sequence and domain structure to the c-fps/fes gene product. We show that FER and flk are human and rat counterparts of an evolutionarily conserved gene, hereafter termed FER regardless of species. The human and rat FER genes encode a widely expressed 94-kilodalton protein-tyrosine kinase which is antigenically related to the fps/fes protein-tyrosine kinase. The structural and antigenic similarities between the FER and fps/fes proteins suggest that they are members of a new family of nonreceptor protein-tyrosine kinases.

Animals↗
PubMed1989

Isolation and sequence analysis of a novel human tyrosine kinase gene.

Using v-abl probes, we have identified and cloned a novel fes/fps-homologous human cDNA, which we have designated FER (pronounced "fair"). This apparently full-length cDNA of 3.0 kilobases has an open reading frame of 2,466 base pairs and the capacity to encode a protein of 94,000 molecular weight. The cDNA contains regions homologous to the highly conserved tyrosine protein kinase domain of other oncogenes and growth factor receptors but lacks a clear transmembrane region, indicating that it encodes a tyrosine kinase of the nonreceptor type. The deduced amino acid sequence of FER resembles that of c-fes/fps. Our data indicate that the protein product of FER, p94FER, corresponds to a previously reported cellular phosphoprotein, NCP94, detected with a v-fps-specific antipeptide antiserum.

Amino Acid Sequence↗
PubMed1989

Molecular characterization of variant translocations in chronic myelogenous leukemia.

Five to ten percent of the Ph-positive cases of chronic myelogenous leukemia (CML), termed variant translocations, involve at least one chromosome in addition to 9 and 22 in the abnormality. The involvement of chromosome 9 band q34, where the c-abl oncogene has been localized, is not always cytogenetically detectable in so called variant translocations due to complex rearrangements. We present two cases having the most frequently involved chromosomes (#3 and #17) in such translocations. In one case, both chromosome 9's were cytogenetically normal while in the other, band 9q34 was so called 'masked' or 'hidden'. After molecular evaluation using in situ hybridization and Southern blotting techniques, the involvement of the altered bcr/abl gene was demonstrated and the cytogenetic analysis was revised. Utilization of molecular probes in the evaluation of such cases should become a routine diagnostic procedure in detecting the exchange of bcr and c-abl sequences.

Adult↗
PubMed1989

The bcr gene in Philadelphia chromosome positive acute lymphoblastic leukemia.

In chronic myelogenous leukemia (CML) and in a percentage of childhood and adult acute lymphoblastic leukemia (ALL) the Philadelphia (Ph') chromosome is present in the leukemic cells of patients. This chromosome is the result of a reciprocal translocation between chromosomes 9 and 22. In CML the break on chromosome 22 occurs within the major breakpoint cluster region (Mbcr) of the bcr gene. In this study, we report on the examination of DNAs from nine Ph'-chromosome positive ALL patients for rearrangements within the bcr gene using Southern blot analysis. Of nine patients having a karyotypically identifiable Ph'-chromosome, only five exhibited rearrangements of the bcr gene. This could indicate that in ALL, chromosome 22 sequences other than the bcr gene are involved in the Ph'-translocation. Within the group of Ph'-positive ALL patients having a bcr gene breakpoint, a correlation appears to exist between the age of the patient and the location of the breakpoint within the gene: all or the vast majority of pediatric patients analyzed to date do not have a Mbcr breakpoint as found in CML and in adult ALL.

Adolescent↗
PubMed1988

The first BCR gene intron contains breakpoints in Philadelphia chromosome positive leukemia.

The hallmark of chronic myelogenous leukemia (CML) is a translocation between chromosomes 9 and 22 - the Philadelphia (Ph') translocation. The translocation is also found in acute lymphocytic leukemia (ALL) albeit in a lower percentage of patients. The breakpoint on chromosome 22 is located within the BCR gene: in CML, breakpoints are clustered within 5.8 kb of DNA, the major breakpoint cluster region (Mbcr). In ALL, breakpoints have been reported within the Mbcr but also in more 5' regions encompassing the BCR gene. To characterize the latter breakpoints, we have molecularly cloned and mapped the entire gene, which encompasses approximately 130 kb of DNA. Mbcr negative, Ph'-positive ALL breakpoints were not distributed at random within the gene but rather were found exclusively within the 3' half of the first BCR gene intron. In contrast to the Mbcr, which is limited to a region of 5.8 kb, this part of the intron has a size of 35 kb. Translocation breakpoints in this region appear to be specific for ALL, since it was not rearranged in clinically well-defined CML specimens nor in any other tumor DNA samples examined.

Base Sequence↗
PubMed1988

Duplication of the bcr and gamma-glutamyl transpeptidase genes.

The Philadelphia (Ph') translocation involves rearrangement of the bcr gene located on chromosome 22. Hybridization experiments revealed the presence of multiple bcr gene-related loci within the human genome. Two of these were molecularly cloned and characterized. Both loci contain exons and introns corresponding to the 3' region of the bcr gene. Restriction enzyme and DNA sequence analysis indicate a very high degree of conservation between bcr and the two related genomic sequences. Both bcr-related loci are located on chromosome 22, one centromeric, the other telomeric, of the bcr gene. Within the two bcr related genomic sequences, fragments or the complete coding sequences of an unrelated gene were found to be present. This gene was identified; it encodes gamma-glutamyl transferase, an enzyme involved in the glutathione metabolism.

Animals↗
PubMed1988

Cloning and nucleotide sequence of human gamma-glutamyl transpeptidase.

We have identified the gene for human gamma-glutamyl transpeptidase [GGT; glutamine:D-glutamyl-peptide 5-glutamyltransferase (also called gamma-glutamyltransferase), EC 2.3.2.2] in a BCR gene-related region located in band q11----qter of chromosome 22. Two cDNAs complementary to the GGT mRNA have been isolated from a human placental library constructed in phage lambda gt11. The largest cDNA has a size of 2535 base pairs (bp) and an open reading frame of 1707 nucleotides encoding 569 amino acids. By using a probe corresponding to this cDNA, a mRNA of approximately 2.4 kilobases was detected by RNA blot-hybridization analysis in mouse kidney RNA. The GGT precursor encoded by the coding sequence would have an estimated Mr of 61,400. We compared our nucleotide and deduced amino acid sequences with the published results of rat kidney cDNAs. The human and rat amino acid sequences are similar; however, a considerable discrepancy in nucleotide sequence was found within a 180-bp fragment of the heavy chain, resulting in a completely different amino acid sequence for this region. In addition, the 5' untranslated sequence of the human cDNA (669 bp) is substantially larger than that determined in the rat cDNA (227 bp). Our results may be valuable for further studies on the protein structure of human GGT as well as studies on the regulation of the enzyme.

Amino Acid Sequence↗
PubMed1987

Unique fusion of bcr and c-abl genes in Philadelphia chromosome positive acute lymphoblastic leukemia.

The Philadelphia (Ph) chromosome, the product of t(9:22), is the cytogenetic hallmark of chronic myelogenous leukemia. The c-abl oncogene on chromosome 9 is translocated to the Ph chromosome and linked to a breakpoint cluster region (bcr), which is part of a large bcr gene. This results in the formation of a bcr-c-abl fusion gene, which is transcribed into an 8.5 kb chimeric mRNA encoding a 210 kd bcr-c-abl fusion protein. The Ph chromosome is also found in acute lymphoblastic leukemia (Ph+ ALL). Although the c-abl is translocated and a new 190 kd c-abl protein has been identified, no breakpoints are observed in the bcr (Ph+bcr- ALL). Here we show that in Ph+bcr- ALL, breakpoints in chromosome 22 occur within the same bcr gene, but more 5' of the bcr. Cloning of a chimeric bcr-c-abl cDNA demonstrates that the fusion gene is transcribed into a 7 kb mRNA, encoding a novel fusion protein.

Base Sequence↗
PubMed1987

The BCR/ABL hybrid gene.

A DNA region on chromosome 22, designated M-BCR, contains the chromosomal breakpoint of the Philadelphia (Ph) translocation in all Ph positive CML patients studied to date. M-BCR is part of a gene, BCR, oriented with its 5' end towards the centromere of chromosome 22. All of the CML DNAs analysed have a breakpoint within introns of the BCR gene. As a consequence of the Ph translocation the 3' end of the BCR gene has been translocated to chromosome 9, while the 5' part remains on the Ph chromosome. The remaining BCR sequences act as an acceptor for a chromosome 9 gene, the ABL oncogene: the ABL oncogene is fused in a head-to-tail fashion to the chromosome 22 sequences. This genomic configuration results in the transcription of a novel chimeric mRNA consisting of 5' BCR sequences and 3' ABL oncogene sequences. In K562, a cell line derived from a CML patient, and in five CML patients such chimeric BCR/ABL transcripts have been demonstrated. An abnormally sized ABL protein has been detected in the cell line K562 and in leukaemic cells from patients. This protein represents the translational product of the chimeric mRNA. The role of the BCR part of the fusion protein is unknown; it is possible that the BCR moiety could alter the structure of the ABL protein and unmask its tyrosine kinase activity. By analogy with the gag/v-abl polyprotein, the CML-specific BCR/ABL protein might have transforming activity and could play an essential role in the generation and/or maintenance of CML.

Animals↗
PubMed1987

Evidence that the phl gene encodes a 160,000-dalton phosphoprotein with associated kinase activity.

In chronic myelocytic leukemia, the human c-abl oncogene is translocated from chromosome 9 to a region on chromosome 22 designated as the breakpoint cluster region (bcr) (A. de Klein, A. Guerts van Kessel, G. Grosveld, C. R. Bartram, A. Hagemeyer, D. Bootsma, N. K. Spurr, N. Heisterkamp, J. Groffen, and J. R. Stephenson, Nature (London) 300:765-767, 1982; J. Groffen, J. R. Stephenson, N. Heisterkamp, A. de Klein, C. R. Bartram, and G. Grosveld, Cell 36:93-99.) Abnormal c-abl homologous mRNA and protein have been detected in the leukemic cells of patients with chronic myelocytic leukemia (E. Canaani, D. Stein-Saltz, E. Aghai, R. P. Gale, A. Berrebi, and E. Januszewicz, Lancet 1:593-595, 1984; S. J. Collins and M. T. Groudine, Proc. Natl. Acad. Sci. USA 80:4813-4817, 1983; R. P. Gale and E. Canaani, Proc. Natl. Acad. Sci. USA 81:5648-5652, 1984; J. B. Konopka, S. M. Watanabe, J. W. Singer, S. J. Collins, and O. N. Witte, Proc. Natl. Acad. Sci. USA 82:1810-1814, 1985). The abnormal mRNA represents a chimeric transcript consisting of 5' bcr and 3' c-abl sequences (G. Grosveld, J. Verwoerd, T. van Agthoven, A. de Klein, K. L. Ramachandran, N. Heisterkamp, K. Stam, and J. Groffen, Mol. Cell. Biol. 6:607-616, 1986; E. Shtivelman, B. Lifshitz, R. B. Gale, and E. Canaani, Nature (London) 315:550-554, 1985; K. Stam, N. Heisterkamp, G. Grosveld, A. de Klein, R. S. Verma, M. Coleman, H. Dosik, and J. Groffen, N. Engl. J. Med. 313:1429-1433, 1985). In the present study, we demonstrated that the abnormal c-abl protein is a fusion protein. In addition, the normal gene encompassing bcr sequences was shown to encode a 160,000-dalton phosphoprotein with an associated serine or threonine kinase activity. We propose that this gene be designated phl, reserving the term bcr for the region within the phl gene encompassing the Ph' translocation breakpoints.

Cell Line↗
PubMed1987

Molecular lesion in chronic granulocytic leukemia is highly conserved despite ethnic and geographical variation.

Leukemic cell DNA from patients with Philadelphia chromosome positive chronic granulocytic leukemia in the United Kingdom, Taiwan, and South Africa and of diverse ethnic origins all have identifiable molecular rearrangements of the breakpoint cluster region on chromosome 22 band q11 when screened with an appropriate DNA probe. This result reinforces the highly conserved nature of the molecular lesion in chronic granulocytic leukemia and its suitability as a diagnostic marker for the disease. Since the assay can be performed by sample referral on relatively small numbers of nondividing frozen or dead cells, it is ideally suited for large scale epidemiological and clinical studies, particularly in developing countries where karyotyping services are not readily available.

Chromosome Mapping↗
PubMed1987

Deletion of c-fms sequences in the 5q- syndrome.

Southern blot analyses demonstrated hemizygosity of c-fms sequences in three cases of the 5q- syndrome, cytogenetically characterized by del(5)(q13;q35) or del(5)(q31;q35). In situ hybridization studies revealed a deletion of this oncogene from the 5q- chromosome in two cases; moreover, we localized c-fms to region 5q31-33.

Chromosome Aberrations↗