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I R Kirsch

Publications and source records attributed to I R Kirsch.

At least 91 records · Page 5Linked to original sources
PubMed1986

Bovine galactosyltransferase: identification of a clone by direct immunological screening of a cDNA expression library.

A 1.3-kilobase cDNA clone (7A) coding for bovine galactosyltransferase (glycoprotein 4-beta-galactosyltransferase, EC 2.4.1.38) was isolated from a lambda gt11 expression library by immunological screening with monospecific polyclonal antisera to the affinity-purified bovine enzyme. The nucleotide sequence of this clone predicts an open reading frame that starts at the 5' end of the insert and codes for a polypeptide of 334 amino acids with Mr 37,645. Based on a Mr of 57,000 for the membrane-bound enzyme this clone accounts for approximately 61% of the coding sequence. Portions of the predicted amino acid sequence matched the six tryptic peptides isolated from affinity-purified bovine galactosyltransferase. Clone 7A hybridizes to a 4.8-kilobase bovine mRNA and identifies multiple EcoRI restriction fragments in bovine, murine, and human DNA.

Amino Acid Sequence↗
PubMed1986

Detection and localization of an extra HLA locus in a karyotypically normal male by chromosomal in situ hybridization.

The codominant expression of three HLA haplotypes was found in a healthy 21-year-old Black male, whose prometaphase karyotype was normal by light microscopy. He was the sibling of an antenatally diagnosed female fetus with a partial duplication of 6p. The duplication arose from a complex presumably balanced maternal chromosome rearrangement: 46,XX,dir ins(14;6)(14pter----14p11::6p22----6p21.1::14 p11----14qter; 6pter----6p22::6p21.1----6qter). Chromosomal in situ hybridization using a tritium-labeled genomic clone corresponding to a class I HLA gene revealed two sites of hybridization: at 6p21.3, the band to which this probe has been assigned in normal individuals (Morton et al. 1984a) and a second site at 6p11. We postulate that a recombinational event during meiotic pairing in the mother led to the reintroduction into the normal chromosome 6 homolog of a small segment of the original insertion in chromosome 14 which contained the HLA-A and -B determinants.

Chromosome Banding↗
PubMed1986

Establishment and characterization of a human plasma cell myeloma culture having a rearranged cellular myc proto-oncogene.

Using a serum-free defined medium, we have established a human cell line, NCI-H929, from a malignant effusion occurring in a patient with IgAk myeloma. The cultured cells have the morphologic, ultrastructural, biochemical, immunologic, and cytochemical features of plasma cells. The cells have rearranged alpha and kappa genes and synthesize and secrete high amounts of IgAk (greater than 80 micrograms/10(6) cells per 24 hours). The cells express surface immunoglobulin (alpha and kappa), the plasma cell antigen PCA-1, the transferrin receptor (T9) and T10 but lack antigens associated with earlier stages of B cell development (HLA-DR, B1, B2, B4, CALLA), as well as other leukocyte-macrophage antigens and Epstein-Barr virus (EBV) nuclear antigen. Although molecular studies confirm that both the tumor and cultured cells are derived from the same clone of malignant B cells, the tumor cells were predominantly near-diploid, whereas the cultured cells are predominantly near-tetraploid with six copies of chromosome 8, four to six of which have an 8q + abnormality. However, both the tumor and the cultured cells have a rearrangement of the cellular c-myc proto-oncogene (located at 8q24) and express c-myc RNA. Although a modest number of human "plasmacytoid" cell lines have been established, most are lymphoblastoid lines lacking plasma cell features, while others appear to be early secretory cells. In contrast, NCI-H929 is a differentiated, highly secretory human plasma cell line.

B-Lymphocytes↗
PubMed1985

T cell receptor alpha chain genes are located on chromosome 14 at 14q11-14q12 in humans.

A cDNA clone encoding the alpha chain of the human T cell receptor was used in connection with somatic cell human-rodent hybrids to determine that the genes coding for the alpha chain are located on chromosome 14 in humans. In situ hybridization confirms this result and further localizes these genes to 14q11-14q12 on this chromosome. Since this region of chromosome has been shown to be nonrandomly involved in a number of T cell neoplasias, this assignment raises a number of interesting questions as to the possible involvement of the T cell receptor alpha chain genes in tumorigenesis.

Animals↗
PubMed1985

Translocations that highlight chromosomal regions of differentiated activity.

The frequent translocation of the c-myc oncogene into the immunoglobulin loci in tumors of B lymphocytes prompted us to ask whether or not disease-associated chromosomal translocations specific for other disorders in different cell types would also involve regions of the genome encoding important differentiation-specific products made by these cells. We have studied the karyotypes of two patients with erythroleukemia and an established erythroleukemia cell line, K562 (late passages), and find translocations within the chromosomal regions to which the genes that encode alpha and beta globin have been assigned. Additionally, we have analyzed the karyotype of cloned B-lymphocytes, including both kappa and lambda producing cells, from a patient with ataxia telangiectasia (AT) and find a translocation between the regions encoding immunoglobulin (Ig) light and heavy chain genes whereas a different translocation not involving these regions is seen in T-lymphocytes from the same patient. These examples provide insight into the mechanism of chromosomal translocation in both cancerous and noncancerous conditions and lead to the speculation that genomic activity is a necessary factor in the generation of some chromosomal translocations.

Adult↗
PubMed1985

Burkitt lymphoma cell line carrying a variant translocation creates new DNA at the breakpoint and violates the hierarchy of immunoglobulin gene rearrangement.

The Burkitt lymphoma cell line KK124, which contains a reciprocal t(8;22) translocation, was shown to have rearranged in a region 3' to the c-myc proto-oncogene on chromosome 8 and 5' to the lambda constant region on chromosome 22. The breakpoint was cloned and sequenced, revealing that c-myc and a portion of its 3' region abutted a complete lambda variable gene that had undergone V-J recombination. Since this cell line expresses kappa light chain, this lambda rearrangement violates the previously proposed hierarchy of immunoglobulin gene rearrangement. A novel duplication of normal chromosome 8 sequences was also found at the breakpoint. The first exon of c-myc and its flanking sequence from the translocated allele was sequenced and compared with a normal counterpart. Extensive mutation was found within the first exon in contrast to its 3' and 5' flanking regions. S1 nuclease analysis revealed that it was the translocated c-myc being expressed and that there was a promoter shift from P2 to P1. The detailed structural analysis of this cell line provides clues concerning mechanisms of chromosomal translocation and c-myc deregulation in Burkitt lymphomas.

Amino Acid Sequence↗
PubMed1985

NIH conference. Molecular genetic analysis of human lymphoid neoplasms. Immunoglobulin genes and the c-myc oncogene.

Immunoglobulin genes responsible for individual antibodies are organized as discontinuous DNA segments in their germline form. As an uncommitted stem cell develops into an antibody-synthesizing plasma cell, rearrangements of these immunoglobulin gene segments serve to activate the genes and to generate the virtually unlimited capacity to synthesize antibodies that recognize potential antigens. The analysis of immunoglobulin gene structure and arrangement has been of immense value in the study of human lymphoid neoplasms. Recombinant DNA technology involving analysis of immunoglobulin gene arrangement has been used to classify neoplasms of previously uncertain lineage, aid in the diagnosis of neoplasms of the B-cell series, and define the state of differentiation of neoplastic B-cell precursors. Furthermore, the demonstration of translocation of a particular transforming gene, the c-myc oncogene, into the immunoglobulin gene locus in Burkitt's lymphoma has provided a major insight into the cause of malignant transformation of these lymphoid cells.

Alleles↗
PubMed1984

Orientation of loci within the human major histocompatibility complex by chromosomal in situ hybridization.

We have determined the localization and orientation of two genetic probes within the human major histocompatibility complex by chromosomal in situ hybridization. Our data indicate that a cloned genomic probe cross-hybridizing to HLA-A, -B, and -C heavy chain loci is homologous to sequences located on chromosome 6 at band p21.3 while a subclone of the genomic HLA-DR alpha-chain gene corresponding to the nonpolymorphic p34 protein is homologous to sequences in band 6p21.1. Our data suggest that this technique may permit the estimation of map distances between linked gene loci, assuming a uniform frequency of map units in the human genome. The relative positions of these genes was confirmed in a mother and son carrying a chromosome rearrangement involving 6p and 14p in which the sequences hybridizing to a DR alpha-chain genomic clone were found at the distal end of the 6p--chromosome [der(6)] while the sequences hybridizing to the HLA-A, -B, -C alpha-chain probe were found in the 14p+ chromosome [der(14)].

Chromosome Mapping↗
PubMed1984

Localization of the beta-globin gene by chromosomal in situ hybridization.

A 3.7-kilobase (kb) genomic clone of the human beta-globin gene, including 1.5-kb upstream and approximately 0.5-kb downstream, was utilized in chromosomal in situ hybridization for precise mapping of the beta-globin locus on peripheral blood lymphocyte-derived metaphases from a normal male, and for further evaluation of a clonal t(7;11) (q22;p15) translocation on bone marrow-derived metaphases from a 46-year-old male with erythroleukemia. Analyses of 205 midmetaphases from a normal male hybridized with the tritium-labeled beta-globin probe and stained with quinacrine mustard dihydrochloride revealed approximately 12% of spreads to have silver-grain deposition over the p15 band of chromosome 11. Of the 365 silver grains observed to be located on or beside chromosomes, 25 (approximately 7%) grains were localized in band p15. Karyotype analysis of a bone marrow specimen from the patient with erythroleukemia revealed hypodiploidy with various unidentified marker chromosomes as well as a presumably balanced translocation between 7q and 11p . Chromosomal in situ hybridization showed localization of silver grains at the junction between chromosomes 7 and 11 as well as to the normal chromosome 11, indicating that the beta-globin locus had not been translocated in the chromosomal rearrangement. This case demonstrates the value of chromosomal in situ hybridization in the definition of chromosome rearrangements and provides further evidence for the localization of the beta-globin gene to 11p15 .

Chromosome Banding↗
PubMed1982

Duplication and deletion in the human immunoglobulin epsilon genes.

The human IgE gene encodes a polypeptide chain that is involved in allergic reactions and in the immune response to parasitic disease in man. We have cloned three chromosomal regions corresponding to this sequence and find that two of them derive from curiously duplicated gene segments that also encode IgA constant-region genes. One of the IgE sequences corresponds to the active gene, and its structure defines a complete amino acid sequence of the human IgE constant region. The other cloned segment is a pseudogene from which the first two IgE coding domains have been deleted and replaced by a switch-like sequence that also occurs close to the normal IgE gene. The third IgE segment remains unlinked to the other heavy-chain genes. Evidently, the epsilon-alpha locus has been the site of several complicated genetic rearrangements during recent evolutionary time.

Amino Acid Sequence↗
PubMed1980

Evolutionary approach to the question of immunoglobulin heavy chain switching: evidence from cloned human and mouse genes.

We have used cloned mouse and human heavy chain genes to identify regions of conserved homology between mouse and man and between mu and alpha genes. Using heteroduplex mapping, we find that coding segments for homologous domains appear to have been well conserved between the two species, but the short intervening sequences that separate domains have diverged considerably. These studies also identify extensive regions of homology 5' to both mu and alpha constant region genes that are conserved between the two genes as well as between mouse and man. These segments encompass regions in which mu/alpha recombination occurs during the heavy chain class switch, and their extensive homology may be relevant to this process.

Animals↗
PubMedDate not supplied

L-myc, a new myc-related gene amplified and expressed in human small cell lung cancer.

Altered structure and regulation of the c-myc proto-oncogene have been associated with a variety of human tumours and derivative cell lines, including Burkitt's lymphoma, promyelocytic leukaemia and small cell lung cancer (SCLC). The N-myc gene, first detected by its homology to the second exon of the c-myc gene, is amplified and/or expressed in tumours or cell lines derived from neuroblastoma, retinoblastoma and SCLC. Here we describe a third myc-related gene (L-myc) cloned from SCLC DNA with homology to a small region of both the c-myc and N-myc genes. Human genomic DNA shows an EcoRI restriction fragment length polymorphism (RFLP) of L-myc defined by two alleles (10.0- and 6.6-kilobase (kb) EcoRI fragments), neither associated disproportionately with SCLC. Mouse and hamster DNAs exhibit a 12-kb EcoRI L-myc homologue, which indicates conservation of the gene in mammals. Gene mapping studies assign L-myc to human chromosome region 1p32, a location distinct from that of either c-myc or N-myc but associated with cytogenetic abnormalities in certain human tumours. This L-myc sequence is amplified 10-20-fold in four SCLC cell line DNAs and in one SCLC tumour specimen taken directly from a patient. Either the 10.0- or 6.6-kb allele can be amplified and in heterozygotes only one of the two alleles was amplified in any SCLC genome. SCLC cell lines with amplified L-myc sequences express L-myc-derived transcripts not seen in SCLC with amplified c-myc or N-myc genes. In addition, some SCLCs without amplification also express L-myc-related transcripts. Together, these findings suggest an enlarging role for myc-related genes in human lung cancer and provide evidence for the concept of a myc family of proto-oncogenes.

Amino Acid Sequence↗