PubMed Health⌕ Search

Biomedical subjects

B D Young

Publications and source records attributed to B D Young.

At least 19 recordsLinked to original sources
PubMed1995

The leukemia-associated-protein (LAP) domain, a cysteine-rich motif, is present in a wide range of proteins, including MLL, AF10, and MLLT6 proteins.

We have identified and further characterized a Caenorhabditis elegans gene, CEZF, that encodes a protein with substantial homology to the zinc finger and leucine zipper motifs of the human gene products AF10, MLLT6, and BR140. The first part of the zinc finger region of CEZF has strong similarity to the corresponding regions of AF10 (66%) and MLLT6 (64%) at the cDNA level. As this region is structurally different from previously described zinc finger motifs, sequence homology searches were done. Twenty-five other proteins with a similar motif were identified. Because the functional domain of this motif is potentially disrupted in leukemia-associated chromosomal translocations, we propose the name of leukemia-associated protein (LAP) finger. On the basis of these comparisons, the LAP domain consensus sequence is Cys1-Xaa1-2-Cys2-Xaa9-21-Cys3-Xaa2-4 -Cys4-Xaa4-5-His5-Xaa2-Cys6-Xaa12-46 - Cys7-Xaa2-Cys8, where subscripted numbers represent the number of amino acid residues. We review the evidence that this motif binds zinc, is the important DNA-binding domain in this group of regulatory proteins, and may be involved in leukemogenesis.

Amino Acid Sequence↗
PubMed1995

Breakpoint heterogeneity in t(10;11) translocation in AML-M4/M5 resulting in fusion of AF10 and MLL is resolved by fluorescent in situ hybridization analysis.

Ten AML-M4/M5 patients' samples containing a t(10;11) translocation, but with different cytogenetic breakpoints on chromosome 11q (11q13-23), were studied by G- and R-banding and fluorescent in situ hybridization. Southern blotting analysis, studied in five patients, revealed a rearranged MLL gene. Reverse transcription-PCR analysis carried out in six patients showed a 5' MLL-3' AF-10 fusion transcript. Fluorescent in situ hybridization studies suggested that in 8 of 10 patients, the rearrangement/fusion transcript resulted from an inversion of a part of 11q (q13q23) translocated to 10p12. In the other two patients, it is assumed that an inversion/translocation has occurred of a part of 10p to the der(11). The results suggest that the orientation of the AF-10 gene on 10p is 5' telomeric and 3' centromeric. This is the first example of opposite-oriented genes being involved in translocation to yield fusion transcripts.

Adult↗
PubMed1995

The t(10;11) translocation in acute myeloid leukemia (M5) consistently fuses the leucine zipper motif of AF10 onto the HRX gene.

The gene on chromosome 10 at band p12 (AF10), involved in the t(10;11) translocation in acute myeloid leukemia, has been identified and shown to contain conserved zinc finger and leucine zipper domains. These regions are highly homologous to the equivalent regions on AF17, the gene involved in the t(11;17) translocations. A series of adult, childhood, and infant leukemias with either simple or complex versions of the t(10;11) has been examined by Southern analysis and shown to involve rearrangement to the HRX locus. Reverse transcriptase-polymerase chain reaction from either bone marrow or peripheral blood cells showed that HRX sequence was fused to AF10 sequence in all 8 cases and subsequent sequence analysis showed an in-frame fusion between the HRX and AF10 sequence. A consistent feature of these fusions was the juxtaposition of the leucine dimerization motif of AF10 onto the NH2-terminal region of HRX. The published data suggest that a similar conclusion can be drawn about the t(11;17) translocation, implying a critical role for this motif in the chimaeric HRX protein.

Adult↗
PubMed1995

A novel class of zinc finger/leucine zipper genes identified from the molecular cloning of the t(10;11) translocation in acute leukemia.

A novel class of conserved transcription factors has been identified from the molecular cloning of AF10, the gene involved in the t(10;11)(p12;q23) translocation of acute myeloid leukemias. AF10 encodes a 109-kD protein of 1,027 amino acids and contains an N-terminal zinc finger region and a C-terminal leucine zipper. These structures have been found to be conserved in sequence and position in three other proteins, AF17, BR140, and a previously unrecognized Caenorhabditis elegans gene, provisionally named CEZF. The overall structure, level of sequence conservation, and expression pattern suggest that these genes encode a new class of transcription factors, some of which are targets for chromosomal translocation in acute leukemia.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Acceleration of experimental lapine osteoarthritis by calcium pyrophosphate microcrystalline synovitis.

OBJECTIVE: To investigate the effects of chronic calcium pyrophosphate dihydrate (CPPD) synovitis on the development of osteoarthritic (OA) lesions in an animal model. METHODS: OA was induced in the right knees of 30 male New Zealand white rabbits by partial lateral meniscectomy and section of the fibular collateral and sesamoid ligaments (PLM/LS), followed by 8 weekly intraarticular (IA) injections of 1 mg (low-dose) or 10 mg (high-dose) of CPPD crystals in 3 sets of experiments (10 rabbits each). The contralateral left knees served as controls: experiment 1 PLM/LS alone, experiment 2 8 weekly IA injections of CPPD crystals alone, and experiment 3 sham surgery plus 8 weekly IA injections of CPPD crystals. RESULTS: At 8 weeks, repeated IA injections of low-dose and high-dose CPPD crystals into meniscectomized right knees resulted in more severe OA than in meniscectomized but noninjected left knees (experiment 1) (P = 0.003 and P = 0.001, respectively). One-fourth of the meniscectomized knees (11 of 40), both CPPD-injected and noninjected, showed embedded synovial cartilage shards. CONCLUSION: The data demonstrate a worsening effect of chronic CPPD crystal-induced synovitis on experimental OA produced in the rabbit knees by PLM/LS, and support a possible role for CPPD microcrystalline inflammation in the progression of OA lesions in clinical CPPD crystal deposition disease.

Animals↗
PubMed1995

Induction of CD80 expression in low-grade B cell lymphoma--a potential immunotherapeutic target.

The CD80 antigen (B7) is expressed on activated B lymphocytes. It is thought to be important in eliciting a T cell response via its ligands CD28 and CTLA-4 when antigen is presented in the presence of the MHC-1 peptide. Low-grade B cell lymphomas analysed by flow cytometry express CD80 very poorly. However, when grown in vitro using the IL-4/anti-CD40 stromal cell culture system, following depletion of T and IgD-bearing cells, a monoclonal B cell expansion occurs. Cells harvested at days 10-13 express the antigen strongly, regardless of the histological subtype of lymphoma. Further investigation of CD80-mediated immune functions may be possible using this system as a basis for testing immunotherapy.

B7-1 Antigen↗
PubMed1994

Prevalence and clinical correlations of MLL gene rearrangements in AML-M4/5.

Rearrangements of the human trithorax gene (MLL, HRX, Htrx-1, All-1) were studied by Southern blotting in blast cells stored at presentation from 65 adults with de novo acute myelomonocytic (AML-M4) and acute monocytic leukemia (AML-M5). MLL rearrangements were demonstrated in 15 (23%) cases, including eight patients in whom karyotype analysis had failed to detect abnormalities of chromosome band 11q23. The patients with MLL rearrangements did not differ significantly from those with germline configurations in terms of the sex and age of the patients, the presence of lymphadenopathy, hepatosplenomegaly, or central nervous system involvement, and the absolute blast count at diagnosis. Kaplan-Meier analysis of the treated patients demonstrated no difference in survival for patients with MLL rearrangements compared with those without rearrangements. Therefore, in contrast to infantile acute leukemia, in adults with AML-M4 and AML-M5, MLL rearrangements do not identify a subgroup of patients with different clinical features or prognosis.

Adolescent↗
PubMed1994

Fluorescence in situ hybridization analysis using cosmid probes to define chromosome 6q abnormalities in ovarian carcinoma cell lines.

Deletion of 6q is a frequent finding in ovarian carcinoma, which would suggest that this region contains one or more putative tumor suppressor genes. Chromosome 6q abnormalities in six ovarian carcinoma cell lines were analyzed by G-banding and fluorescence in situ hybridization (FISH). Using a variety of probes, including a chromosome 6 paint, a probe specific for the chromosome 6 centromere, and cosmids that map to q24 (cCI6-115), q25 (cCI6-4), q26 (cCI6-91, cCI6-119), and q27 (cCI6-13, cCI6-24, and cCI6-111), abnormalities of 6q were found in three cell lines. In cell line OAW42 (hypotetraploid), the sequences complementary to cCI6-119, cCI6-91, and cCI6-13 probes were lost in two homologues of chromosome 6, which indicates the deletion of genetic material from bands q26-27. The same bands were translocated in cell line PEO1 (hypertriploid). The probes from this region were absent on two copies of chromosome 6, but hybridized to two or three markers. In cell line 59M (hyperdiploid) an interstitial deletion proximal to q24 was detected in one chromosome 6. We conclude that it is very likely that a gene or genes localized in bands 6q26-27, and perhaps in the region proximal to 6q24, play a critical role in the development or progression of ovarian carcinoma.

Adenocarcinoma↗
PubMed1994

Molecular cloning of two isoforms of the murine homolog of the myeloid CD33 antigen.

CD33 monoclonal antibodies recognize a 67-kD glycoprotein of unknown function that is expressed by early myeloid progenitors and their leukemic counterparts. We report here the cloning of the murine homolog of the human CD33 antigen. Two cDNA clones, differing by an 83-nucleotide insertion in the cytoplasmic region, were isolated. The insertion generated a shift in the reading frame within the cytoplasmic tail, resulting in two mouse CD33 isoforms, m33-A and m33-B, with distinct cytoplasmic domains and with predicted protein core molecular weights of 37 kD and 45 kD, respectively. The cDNAs and deduced amino acid sequences show extensive similarity with the human CD33 sequence with the highest homology occurring in the first and second lg-like domains (61% amino acid identity). The most significant divergence between the human and murine proteins occurs in their cytoplasmic portions. The murine CD33 mRNAs were detected in bone marrow, spleen, thymus, brain, liver, the multipotential progenitor cell line, A4, the myelomonocytic cell line, WEHI3B, the myeloid cell line, M1, and the macrophage cell line, P388, by Northern blot analysis. The expression pattern of the murine CD33 homolog suggests that the function of CD33 antigen in hematopoiesis may be conserved between humans and mice.

Amino Acid Sequence↗
PubMed1994

Fluorescence in situ hybridisation studies to characterise complete and partial monosomy 7 in myeloid disorders.

Eight patients with myeloid disorders characterised by a karyotype including apparent monosomy or partial monosomy 7, in the presence of a ring or marker chromosome, were investigated by fluorescence in situ hybridisation (FISH) with a chromosome 7 centromere-specific probe and an Alu-PCR derived chromosome 7 paint. In 4 of 5 cases a ring chromosome was shown to be of chromosome 7 origin; in one of these the apparent ring was shown to consist solely of chromosome 7 centromeric material, and in the fifth case the ring was derived from chromosome 18. In three cases monosomy 7 had arisen during the course of karyotype evolution and was clearly not the primary cytogenetic abnormality. One further case demonstrated fragmentation and cryptic translocation of chromosome 7 material. In the last case a chromosome described as der(l)t(1;7)(p11;p11) was redefined as dic(1;7)(p11;q11). The application of FISH has enabled a more accurate characterisation of chromosome abnormalities, and extended studies of this type may eventually lead to more precise prognostic groups defined by karyotype.

Adult↗
PubMed1994

Detection of cells bearing the t(14;18) translocation following myeloablative treatment and autologous bone marrow transplantation for follicular lymphoma.

PURPOSE: To use the polymerase chain reaction (PCR) technique for molecular assessment of the results of myeloablative treatment of follicular lymphoma with autologous bone marrow transplantation. PATIENTS AND METHODS: Seventy-six patients with follicular or transformed follicular lymphoma were treated with cyclophosphamide 60 mg/kg x 2 and total-body irradiation 12 Gy, supported by autologous bone marrow transplantation. The bone marrow mononuclear cell fraction was treated in vitro with CD20 monoclonal antibody and baby rabbit complement. The PCR technique was used to identify 50 patients with amplifiable t(14; 18) translocations in biopsy material from lymph nodes or bone marrow infiltrated by lymphoma. RESULTS: Following treatment of the harvested bone marrow in vitro, 29 samples were tested by PCR to assess the efficacy of purging. In 25 cases, the same t(14; 18) sequences were amplified as from the patients' original biopsies, while in four cases, the marrow became PCR-negative. Three of the four patients treated with PCR-negative marrow subsequently developed recurrent lymphoma, compared with 11 of 25 in the PCR-positive group. Bone marrow and peripheral-blood mononuclear cell samples from 27 patients were studied during the follow-up period. All but one had the presence of the lymphoma-related t(14; 18) clone detectable by PCR and confirmed by direct sequencing from at least one sample between 3 months and 7 years after reinfusion of the bone marrow. With a median follow-up duration of 3 years, 13 patients developed recurrent disease, 13 remained in remission with the t(14; 18) still detectable, and one died of acute myeloid leukemia. CONCLUSION: This form of therapy does not eliminate the lymphoma-related t(14; 18)-bearing clone of cells, although the significance of its continued presence is uncertain. Improved methods for both treatment of the bone marrow in vitro and treatment of the lymphoma in vivo are required.

Adult↗
PubMed1994

Molecular cloning of a novel 11q23 breakpoint associated with non-Hodgkin's lymphoma.

Chromosomal analysis of a non-Hodgkin's lymphoma revealed a t(11;14)(q23;q32) translocation amongst other abnormalities. To investigate the molecular basis of this translocation, a cosmid library was constructed from the tumour DNA and the rearranged IGH locus was isolated in a single cosmid. Fluorescence in situ hybridization confirmed that the cloned region contained sequences from chromosome 11q23 fused to chromosome 14q32. Sequence analysis identified the breakpoint as a fusion between a region from the switch segment of the C gamma 4 gene of the IGH locus and an unknown sequence on chromosome 11. The chromosome 11 sequence maps proximal to the CD3 gene cluster and is therefore distinct from both the HTRX1 gene (rearranged in acute leukaemias) and the RCK gene (rearranged in a cell line derived from a histiocytic B-cell lymphoma). This newly identified region contains a cluster of rare cutting restriction enzyme sites located within 200 bases of the breakpoint, suggestive of a CpG island. Although this t(11;14)(q23;q32) translocation and that in the RC-K8 cell line affect different regions on chromosome 11, the breakpoints on chromosome 14 were found to have occurred at equivalent positions of S gamma 2 and S gamma 4 segments.

Adult↗
PubMed1994

The t(14;18) in a patient with de novo acute lymphoblastic leukemia is associated with t(8;9).

Cytogenetic analysis of a bone marrow aspirate from a patient with acute lymphoblastic leukemia (ALL) revealed the presence of a complex karyotype containing the translocation, t(14;18)(q32;q21). Further investigations using fluorescence in situ hybridization (FISH) allowed the characterization of an additional translocation, t(8;9)(q24;p1?). The association of t(14;18)(q32;q21) and t(8;9)(q24;p13) has recently been described in two patients with de novo ALL (Nacheva et al. Blood 1993;82:231-240) and this report supports these findings.

Adult↗
PubMed1993

In situ hybridisation analysis of a homogeneously staining region at 11q23-24 in an acute myeloid leukaemia (M5) using yeast artificial chromosomes.

An example of a homogeneously staining region (hsr), occurring in an acute myeloid leukaemia (M5) on chromosome 11 in the region of bands q23-q24, has been analysed. In situ hybridisation using yeast artificial chromosome (YAC) DNA demonstrated that the amplification did not include the CD3 gene cluster and did not affect the human trithorax gene known to be disrupted by translocations at 11q23. In contrast, the amplification was shown to include the sequence D11S543 which has been previously mapped to chromosome band 11q24. High resolution analysis using confocal microscopy allowed the individual amplicons to be visualised, and it was shown that the hsr consisted of an 8-fold amplification of the region surrounding the probe D11S543. From previous estimates of human chromosome size it was possible to calculate that the hsr was composed of amplicons approximately 10 megabases in length. It was concluded that the region amplified did not extend as far as the translocation breakpoints occurring at 11q23 in acute leukaemias.

Aged↗
PubMed1992

Direct sequence analysis of the t(14;18) chromosomal translocation in Hodgkin's disease.

There have been conflicting reports about the occurrence of the t(14;18) chromosomal translocation in Hodgkin's disease. A polymerase chain reaction analysis of biopsy specimens from 21 patients with Hodgkin's disease (HD) has shown the presence of the t(14;18) translocation in four cases (20%). All four patients had nodular sclerosing HD. Direct sequencing of the amplified 14q+ junctions established that the BCL-2 (major breakpoint region) sequence was fused to an Ig joining region (JH) (J6 in all four cases). Different breakpoints were observed in each case but were similar in nature to the breakpoints described in follicular lymphoma. The exact nature and cell of origin in HD remains obscure, although the presence of the t(14;18) translocation may reflect either a B-cell origin in these cases or associated lymphoid hyperplasia.

Adolescent↗
PubMed1992

Molecular cloning and analysis of chromosome band 11q23 involved in leukaemia-associated translocations.

Three overlapping yeast artificial chromosomes (YACs) spanning a 780 kb region of DNA around the CD3 locus on chromosome 11 have been isolated and characterised. The individual cloned regions have been mapped by in situ hybridisation to chromosome band 11q23, and a restriction enzyme map of this region has been constructed. The positions of these clones in relation to a series of leukaemia-associated chromosomal translocations has also been determined. It was concluded that, although two clones lay entirely proximal to the breakpoints examined, the third clone (13HH4) encompassed the breakpoints for the translocations t(4;11), t(6;11), and t(9;11). The t(9;11) was observed in an acute myeloid leukaemia in a patient previously treated for an unrelated malignancy. It would thus appear that the breakpoints at chromosome band 11q23 occurring in therapy-related leukaemias are in the same region as those found in adult and childhood acute leukaemias and may result from a common underlying mechanism.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

Fluorescent in situ identification of human marker chromosomes using flow sorting and Alu element-mediated PCR.

A novel approach to the identification of human chromosomes has been developed. Chromosomal in situ hybridization (or "chromosome painting") has been performed using Alu element-mediated PCR products from small quantities (250-500) of flow-sorted normal and abnormal chromosomes. Chromosome paints for various normal chromosomes, including 5, 6, 7, 14, 18, 19, 21, and 22, were generated and shown to be effective in the identification of the appropriate chromosomes. In addition, certain abnormal chromosomes, including a mental retardation-associated deletion chromosome 11 (q22-q23), the products of the constitutional translocation t(11;22), and the CML-associated t(9;22), were used to generate region-specific paints. In each case, the appropriate regions of the chromosomes were highlighted and this strategy is, therefore, well suited to the identification of previously unidentified marker chromosomes. A further direct consequence of this work is that chromosome paints specific for the common aberrant chromosomes, such as the Philadelphia chromosome, can be generated and made widely available. These may find particular use in the analysis of complex or masked chromosomal translocations.

Base Sequence↗