Configuration and expression of the T cell receptor beta chain gene in human T-lymphotrophic virus I-infected cells.

We studied the configuration and expression of the gene encoding the beta chain of the T cell receptor (TCR beta) in cell lines and primary tumor cells infected by the human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I). Most of the cell lines and all the primary tumor cells showed rearrangement of the TCR beta gene, and in each case the rearrangement was distinct. The majority of cases examined were clonal with respect to a particular TCR beta gene rearrangement. Primary tumor cells from one case (SD) were found to have a tandem duplication of a portion of chromosome 7; this appears to have resulted in the presence of three alleles of the TCR beta gene, each of which is arranged differently. This suggests that the chromosomal abnormality, and possibly infection by HTLV-I, occurred before TCR beta gene rearrangement. Cell lines infected by HTLV-I express levels of TCR beta mRNA similar to PHA stimulated lymphocytes, suggesting that this gene is not transcriptionally activated as a result of infection by HTLV-I. Cloned T cells of known antigen specificity that are infected by HTLV-I in vitro show impairment of immune function, including loss of antigen-specific responsiveness and the acquisition of alloreactivity. Comparison of the configuration of the TCR beta gene before and after infection revealed no changes detectable by Southern blot analysis. Levels of expression of the TCR beta gene at the mRNA level and surface expression of the T3 complex were also not significantly altered, suggesting that changes in immune function cannot be attributed to quantitative changes in the TCR molecule. The configuration of the TCR beta gene in primary tumor cells infected by HTLV-I was compared with that in the derived cell lines. In all pairs examined, the configuration in the primary tumor cells was different from that in the cell lines, strongly suggesting that the cells that grow in culture are not the original neoplastic cells.

T cell receptor and immunoglobulin gene rearrangements in acute myeloblastic leukemia.

The organization and expression of the beta chain of T cell antigen receptor gene (beta-TCR) and Ig H and L chain genes were analyzed by Southern blot technique in 24 patients with a diagnosis of acute myeloblastic leukemia (AML). Rearrangements of the beta-TCR genes were seen in DNA samples from 3 of the 24 patients. One of these three patients also showed rearrangement of the Ig H chain gene. RNA samples from all three patients expressed a beta-TCR gene transcript on dot blot analysis. However, on Northern blot analysis, one patient expressed an incomplete 1.0 kb transcript and no Ig H chain mRNA, despite a rearranged configuration. The karyotypes of two of these patients showed abnormalities involving chromosome 7. Rearrangements of T cell antigen receptor genes may occur in nonlymphoid malignancy, and is consistent with the concept of lineage infidelity in AML.

Localization of the human NCAM gene to band q23 of chromosome 11: the third gene coding for a cell interaction molecule mapped to the distal portion of the long arm of chromosome 11.

cDNA clones containing sequences coding for the murine neural cell adhesion molecule (N-CAM) were used in Southern hybridizations on human genomic DNA and demonstrated approximately 90% homology between human and murine NCAM genes. In situ hybridization with one of these clones was performed on human metaphase chromosomes and allowed the localization of the human NCAM gene to band q23 of chromosome 11. The genes for two other cell surface molecules believed to be involved in cell-cell interactions, Thy-1 and the delta chain of the T3-T cell receptor complex, have recently been localized to the same region of chromosome 11 in man. Moreover, this region of the human chromosome 11 appears to be syntenic to a region of murine chromosome 9 that also contains the staggerer locus: staggerer mice show abnormal neurological features which may be related to abnormalities in the conversion of the embryonic to the adult forms of the N-CAM molecule.

Genetic length of a human chromosomal segment measured by recombination between two fragile sites.

Two families were studied in which the same homolog of chromosome pair 10 expressed both the fragile sites on the long (q) arm at 10q23 and 10q25. Recombination between the fragile sites was observed in 3 of the 27 offspring in whom it could occur. The genetic length of chromosome between the fragile sites was 11 female centimorgans within a 95 percent probability interval of 4 to 28 centimorgans. This estimate of genetic length is comparable to those obtained with other methods.

Familial renal cell carcinoma with a 3;11 chromosome translocation limited to tumor cells.

Cytogenic studies were performed on the direct chromosome preparations of the renal cell carcinoma cells and the cultured peripheral blood lymphocytes of a patient with familial renal cell carcinoma. The results revealed a specific, acquired translocations (3p;11p) present in the majority of metaphases of the tumor, indicating that the development of renal cell carcinoma is associated with a deletion in the proximal end of 3p. Renal cell carcinoma is thus the third example--the first two being retinoblastoma and Wilms' tumor--of a chromosomal deletion occurring germinally or somatically in association with a specific tumor. This finding adds further support to the existence of specific human cancer genes.

Amplification and rearrangement of Hu-ets-1 in leukemia and lymphoma with involvement of 11q23.

The Hu-ets-1 oncogene was found to be rearranged and amplified 30-fold in one case of acute myelomonocytic leukemia in which a homogeneously staining region occurred on 11q23; the oncogene was rearranged and amplified approximately tenfold in a case of small lymphocytic cell lymphoma with an inverted insertion that also involved band 11q23. This work suggests that Hu-ets-1 is an unusual oncogene that can help explain the common involvement of chromosome band 11q23 in various subtypes of hematopoietic malignancies.

A distant gene deletion affects beta-globin gene function in an atypical gamma delta beta-thalassemia.

We describe an English family with an atypical gamma delta beta-thalassemia syndrome. Heterozygosity results in a beta-thalassemia phenotype with normal hemoglobin A2. However, unlike previously described cases, no history of neonatal hemolytic anemia requiring blood transfusion was obtained. Gene mapping showed a deletion that extended from the third exon of the G gamma-globin gene upstream for approximately 100 kilobases (kb). The A gamma-globin, psi beta-, delta-, and beta-globin genes in cis remained intact. The malfunction of the beta-globin gene on a chromosome in which the deletion is located 25 kb away suggests that chromatin structure and conformation are important for globin gene expression.

Cloning and sequencing of a c-myc oncogene in a Burkitt's lymphoma cell line that is translocated to a germ line alpha switch region.

We have cloned and sequenced the translocated c-myc gene from the Burkitt's lymphoma CA46 cell line that carries a reciprocal translocation between chromosomes 8 and 14. The breakpoint lies within the first intron of c-myc, so that the first noncoding exon of the gene remains on the 8q- chromosome. The second and third coding exons are translocated to the 14q+ chromosome into the switch region of C-alpha 1. The orientation of the c-myc gene with relationship to alpha 1 is 5' to 5', with directions of transcription in opposite orientation. DNA sequencing studies predict five changes in the amino acid sequence of the myc protein, two of which occur in a region within the second exon which is highly conserved in evolution. Southern blotting data indicate that the first exon of c-myc is rearranged 3' to 3' with the pseudo-epsilon gene. Because CA46 cells contain two rearranged mu genes, the translocation must have occurred after immunoglobulin rearrangement. The position of the breakpoint in CA46 occurs within a 20-base-pair region of the first intron of c-myc to which breakpoints have been mapped for two additional B-cell lymphomas with the t(8;14) translocation, ST486 and the Manca cell line. The region of the heavy chain locus to which c-myc has translocated is different in each case. Comparisons have been made of the levels of transcripts of the translocated c-myc gene in ST486 and CA46, where the gene is not associated with the heavy chain enhancer, with its expression in the Manca cell, in which it is. The c-myc gene is transcribed at similar levels in all three cases.

Chromosome aberrations acquired in vitro by human B-cell lines. II. Distribution of break points.

Among 165 human B-cell lines examined, 57 were found to have karyotypic abnormalities that involved chromosome breakage. The sites of breakage were identified with quinacrine-, Giemsa-, and reverse-banding techniques, and the distribution of 239 break points was plotted. A pronounced excess of telomeric and, to a lesser extent, centromeric breaks was observed. Chromosomes No. 7, 8, 9, 11, and 14 were involved in structural rearrangements more often and chromosomes No. 2, 5, 10, 20, and X less often than was predicted on the basis of their relative lengths. Lines derived from patients with different categories of disorders varied in the distribution of break points throughout the karyotype. In this sample of cell lines, No. 8q; 14q translocations were found only in cultures derived from patients with Burkitt's lymphoma and were never observed to arise among other Epstein-Barr virus-carrying lines even after several hundred cell generations in vitro. An additional feature, which was evidently restricted to lines derived from leukemia or lymphoma patients, was the presence of interstitial insertion, deletion, or reduplication, particularly involving the long arm of chromosome No. 1.

Chromosome aberrations acquired in vitro by human B-cell lines. I. Gains and losses of material.

Gains and losses of chromosomes or chromosome arms were recorded in 45 of 165 human B-cell lines. Most aberrations were acquired in vitro, and their frequency was related to duration of culture. Gains occurred more frequently than losses and their distribution was nonrandom. Chromosomes most commonly affected were No. 3, 7, 8 (particularly 8q), 9, 12, and 21. Certain differences in the frequency of particular aberrations appeared to be related to the clinical conditions of the patients from whom the lines were derived. The distribution of chromosome gains in this material was correlated with those detected in direct preparations from human tumors.

Interstitial deletion of short arm of chromosome 11 limited to Wilms' tumor cells in a patient without aniridia.

An interstitial deletion of the short arm of a chromosome 11 was found in Wilms' tumor cells of a patient without aniridia. The chromosomes in her peripheral blood lymphocytes were normal. The karyotype of the tumor cells is similar to that reported for the somatic cells of patients with aniridia-Wilms' tumor association. We showed that the same cytogenetic change as that seen in patients with this condition, namely, an interstitial deletion of 11p13, can occur in patients without aniridia as a mutation that is confined to tumor cells.

The insulin gene is located on the short arm of chromosome 11 in humans.

The human insulin gene has been previously localized to chromosome 11. We have analyzed the human DNA sequences present in a human-mouse somatic cell hybrid line possessing a translocation involving human chromosomes 11 and X. These data indicate that the human insulin gene is located on the short arm of chromosome 11 in the region p13 leads to pter.

Isolation of human-mouse somatic cell hybrids producing human prolactin: dominant expression of hormone secretion and regulation.

Human PRL (hPRL)-secreting adenoma cells obtained at hypophysectomy were fused with a mutant mouse fibroblast line (LMTK-) which is aminopterin sensitive due to a deficiency in the enzyme thymidine kinase. After fusion with polyethylene glycol, cells containing nuclear material from the two parental lines (heterokaryons) were selected in medium containing hypoxanthine, aminopterin, and thymidine, and resultant clones were screened for hPRL secretion. Functional human X mouse somatic cell hybrid clones secreting hPRL were isolated in order to study hPRL gene expression and regulation. Positive hybrid clones were subcultured and have sustained hPRL secretion. The hybrid nature of the cells was confirmed by fibroblastic morphology resembling the mouse parental cell, mixed karyotype of mouse and human chromosomes, and mixed isozyme banding pattern for human and mouse glucose-6-phosphate dehydrogenase and malic enzyme. Specific expression of the hPRL gene was demonstrated by the presence of electron microscopic secretory granules (650-800 nm), positive immunoperoxidase staining using anti-hPRL serum, and sustained secretion of immunoreactive hPRL, which comigrated with [125I] hPRL standard on Sephadex chromatography. Hormonal modulation of hPRL gene expression by TRH was dominantly expressed in the hybrid cell. Human chromosome 6 was identified in hybrid cells secreting hPRL, and the cells expressed human malic enzyme, a marker for this chromosome, thus confirming the chromosome assignment of the hPRL gene. The results show that functional replicating hybrids secreting hPRL can be isolated. The technique provides a useful in vitro model for the study of hPRL gene expression and modulation.

The anatomy of the human genome.

More than 350 genes have been assigned to specific chromosomes. These include more than 110 assigned to the X chromosome, more than 240 assigned to specific autosomes, and at least one assigned to the Y chromosome. (Even man's 25th chromosome, that of the mitochondrion, is being mapped). Almost all the assignments to specific autosomes were made in the last decade. About half of these were made by study of clones derived from interspecific (e.g., man-mouse) somatic cell hybrids. Over a fifth were made by family linkage studies. Chromosomes 1 and 6 are rather extensively mapped. The genes of over 40 autosomal disorders have been specifically localized. The comparative anatomy, functional anatomy, developmental anatomy and even applied anatomy of the human genome is becoming better known.

New genetics of Burkitt's lymphoma and other non-Hodgkin's lymphomas.

Recent progress in cytogenetics and molecular genetics allows striking new insight into Burkitt's lymphoma. In this B cell tumor, the oncogene c-myc located on the long arm of chromosome 8 translocates to one of three locations: adjacent to the immunoglobulin heavy chain gene on chromosome 14, adjacent to the gene for the kappa light chain of immunoglobulin on chromosome 2, or adjacent to the gene for the lambda light chain on chromosome 22. Nucleotide sequence analysis indicates that the translocated c-myc is usually upstream of an immunoglobulin constant region gene, although the exact position varies. In its new location, the oncogene is actively transcribed and may have escaped its normal control mechanisms. It can be no coincidence that this B cell lymphoma is intimately associated with a misadventure in the genetic underpinnings of the major event in B cell differentiation, the assembling of a functional immunoglobulin molecule. Similar genetic catastrophes probably account for the more common B cell lymphomas and could provide the basis of a coherent lymphoma classification.

Further delineation of the 10p deletion syndrome.

Nine children with a partial deletion of the short arm of the number 10 chromosome have been described in the medical literature. In two new cases of 10p-, the children have several features in common with those previously reported; these features include down-slanting short palpebral fissures, ear anomalies, anteverted nostrils, a short neck, and psychomotor delay. At this stage in the delineation of this condition, the phenotypic expression is variable. However, the craniofacial features of the two children with recently reported 10p- and others display a constellation of individually nonspecific but consistent findings that together form a recognizable gestalt. Pediatric practitioners should consider performing karyotypes in children with developmental disabilities accompanied by multiple structural defects and/or multiple physical variations not part of the family background.

Fragile sites on human chromosomes: description and clinical significance.

The fragile sites of human chromosomes are specific sites that are characterized by a tendency to show gaps, multiradial figures, acentric fragments, and deleted chromosomes on microscopy. These characteristics seem to reflect an inherent fragility at the site, although the underlying biochemical cause of fragile sites is unknown. Investigators have proposed several categories of fragile sites: "rare" or "heritable," "common," and "constitutive." Although the clinical significance of most fragile sites is unknown, fragile site Xq27.3 is associated with one form of X-linked mental retardation. In this article, the three types of chromosome fragile sites are described, and their possible relevance to chromosomal breakage that results in birth defects or cancer is discussed.

Patient with acute B-cell leukemia of Burkitt's type (L3) and marker chromosomes including an (8;14) translocation.

A 20-year-old man with acute B-cell leukemia of Burkitt's type (L3) presenting unusual début symptoms with jaw involvement is reported. The leukemic cells revealed chromosomal abnormalities including four marker chromosomes [1q+, 6q-, t(8;14)].

Chronic T-cell leukemias. II. Cytogenetic studies.

Chromosome abnormalities were documented in the PHA-stimulated lymphoid cells from 10 patients with chronic T-cell leukemias (6 T-PLL, 3 T-CLL and 1 T-LCL). One or more marker chromosomes were present in most metaphases in every case of T-PLL but they were different in each case. Structural abnormalities were also observed in T-CLL and T-LCL but less consistently. Chromosomes involved in marker formation in two or more cases were: Nos. 2, 7, 8, 9, 11 and 16. The karyotype was hypodiploid in five cases and hyperdiploid in two. Chromosomes Nos. 2 and 8 were the most frequently involved in structural and numerical abnormalities: Nos. 8 in 2 T-CLL and the 6 T-PLL and No. 2 in 1 T-CLL, 1 T-LCL and 5 T-PLL. Abnormalities of chromosome No. 2 are rare in human neoplastic disease but may be common in T-lymphoproliferative disorders. The differences between T-PLL and T-CLL reported here may have some bearing on the clinical features. T-PLL, characterised in all cases by clonal abnormalities, has an aggressive clinical course. In contrast, T-CLL with less consistent karyotypic changes has a protracted and benign clinical evolution.

Duplication (12q) syndrome in female cousins, resulting from maternal (11;12) (p15.5;q24.2) translocations.

We have studied female cousins with partial duplication of 12q. The cousins' mothers (who are sisters) and the maternal grandmother and great grandmother carried a balanced translocation between chromosomes 11 and 12. We have compared our patients with eight other reported cases of partial duplication of the same chromosome segment (12q24----12qter). Placement of the extra material seems to have little effect on the anomalies present; (only two other cases involved chromosome 11). We propose that our patients provide further evidence that duplication of 12q leads to a clinically identifiable syndrome.