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Biomedical subjects

J Inazawa

Publications and source records attributed to J Inazawa.

At least 73 records · Page 4Linked to original sources
PubMed1999

Chromosomal imbalances in adult T-cell leukemia revealed by comparative genomic hybridization: gains at 14q32 and 2p16-22 in cell lines.

Comparative genomic hybridization was used to identify chromosomal imbalances in eight cell lines and 12 blood samples from patients with adult T-cell leukemia/lymphoma (ATL). The chromosomes most often over-represented in the cell lines were 2p (6 cases), 7q (4 cases), and 14q (4 cases), with minimal common regions at 2p16-22, 7q21-36, and 14q32, respectively. Distinct imbalances were detected in only 7 of the clinical samples. Chromosomes 14q32 and 2p16-22 harbor TCL1 and a transcription factor, HTLF (human T-cell leukemia virus enhancer factor), respectively. FISH analysis revealed that TCL1 did not juxtapose to TCRA, and we detected no expression of TCL1 in any of the ATL cell lines despite the 14q32 amplifications. Moreover, expression of HTLF was not elevated in the ATL cell lines bearing multiplication of 2p. These results suggest that chromosomal regions 2p16-22 and 14q32 harbor genes other than HTLF and TCL1 that are involved in cellular immortalization or in the pathogenesis of ATL.

Chromosome Aberrations↗
PubMed1999

Genomic structure and chromosomal mapping of the human sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) gene.

Sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) is a central regulator of lipid synthesis and uptake in mammalian cells. The entire genomic structure of the human SCAP gene was cloned in a 110-kb region covered by overlapping genomic clones. The SCAP gene was localized to chromosome 3p21.3 by fluorescence in situ hybridization. The human SCAP gene is over 30 kb in length and contains 23 exons and 22 introns. The transcription initiation site within exon 1 is separate from the initiation codon coded in exon 2. Analysis of exon/intron structure revealed that the gene consists of a mosaic of exons encoding functional protein domains. Exon 1 encodes the 5' non-coding region. Exons 2, 3, 7, 8, 9, 10, 11, 13, and 15, respectively, encode each of the eight transmembrane regions. Of these, exons 7-11 encode the sterol-sensing domain. Exons 15-23 encode the hydrophilic carboxyl-terminal domains containing four copies of a motif called the Trp-Asp (WD) repeats that interact with and regulate SREBP and the site-1 protease. Sequence analysis of the 5'-flanking region showed that it comprised a high G/C-rich region and contained adipocyte determination and differentiation-dependent factor 1 (ADD1)/SREBP-1 binding sites in addition to Sp1 and AP2 sites. This suggests that SCAP gene expression is under the control of SREBP-1, a key regulator of the expression of genes essential for intracellular lipid metabolism. Our data establish the basis of investigation for molecular variants in this gene that may result in alterations in plasma lipoprotein levels and/or derangement of intracellular lipid metabolism.

Base Sequence↗
PubMed1999

The human caspase-activated DNase gene (hCAD): genomic structure, exonic single-nucleotide polymorphisms, and a highly polymorphic dinucleotide repeat at the hCAD locus.

Caspase-activated DNase (CAD) cleaves chromosomal DNA during apoptosis. We determined its genomic structure and identified single-nucleotide polymorphisms (SNPs) within exons 5 and 7, as well as a highly polymorphic dinucleotide repeat of (CT)m(CA)n within the 5' region of the human CAD gene (hCAD). The genomic structure of hCAD presented here, together with information concerning SNPs within the gene, as well as a highly polymorphic (CT)m(CA)n repeat fragment at the hCAD locus, may assist in the construction of genetic maps for exploring gene(s) that play pivotal roles in carcinogenesis.

Deoxyribonucleases↗
PubMed1999

Chromosomal aberrations in human hepatocellular carcinomas associated with hepatitis C virus infection detected by comparative genomic hybridization.

Thirty-five hepatocellular carcinomas (HCCs) associated with hepatitis C virus (HCV) were analysed by comparative genomic hybridization (CGH), to screen for changes in copy-number of DNA sequences. Chromosomal losses were noted in 1p34-36 (37%), 4q12-21 (48%), 5q13-21 (35%), 6q13-16 (23%), 8p21-23 (28%), 13q (20%), 16q (33%) and 17p13 (37%). Gains were noted in 1q (46%), 6p (20%), 8q21-24 (31%) and 17q (43%). High level gains indicative of gene amplifications were found in 7q31 (3%), 11q13 (3%), 14q12 (6%) and 17q12 (3%); amplification at 14q12 may be characteristic for HCCs. No significant difference in chromosomal aberrations was noted between carcinomas associated with HCV-infection in our study and those reported earlier in HCCs infected with hepatitis B virus (HBV), indicating that both HBV- and HCV-related carcinomas may progress through a similar cascade of molecular events.

Carcinoma, Hepatocellular↗
PubMed1999

Identification of BAIAP2 (BAI-associated protein 2), a novel human homologue of hamster IRSp53, whose SH3 domain interacts with the cytoplasmic domain of BAI1.

BAI1 (brain-specific angiogenesis inhibitor 1) was originally isolated as a p53-target gene specifically expressed in brain. To clarify its function, we have been searching for cellular proteins that associate with the cytoplasmic domain of BAI1. Using its intracellular carboxyl terminus as "bait" in a yeast two-hybrid system, we isolated a cDNA clone named BAIAP2 whose nucleotide sequence would encode a 521-amino acid protein showing significant homology to a 58/53-kDa substrate of insulin-receptor kinase in the hamster. As the expression profile of BAIAP2 examined by Northern blot analysis was almost identical to that of BAI1, BAIAP2 appears to be active mainly in neurons. In vitro binding assays confirmed that a proline-rich cytoplasmic fragment of BAI1 interacted with the Src homology 3 (SH3) domain of BAIAP2. Double-color immunofluorescent analysis revealed that BAIAP2 was localized at the cytoplasmic membrane when it was coexpressed with BAI1 in COS-7 cells; BAIAP2 not associated with BAI1 was diffused in the cytoplasm. Predominant localization of BAI1 protein in a sub-cellular fraction enriched in growth cones indicated a possible role of BAI1 as a cell adhesion molecule inducing growth cone guidance. As a protein partner of BAI1, BAIAP2 may represent an important link between membrane and cytoskeleton in the process of neuronal growth.

Amino Acid Sequence↗
PubMed1999

Comparative genomic hybridization of squamous cell carcinoma of the esophagus: the possible involvement of the DPI gene in the 13q34 amplicon.

We investigated copy number aberrations in 29 primary tumors and 12 cell lines of esophageal squamous cell carcinoma (ESC) using comparative genomic hybridization. In the primary tumors, the most common sites of copy number gains were 3q26.3-27 (45%), 8q24 (41%), 5p15 (38%), Xq27-28 (38%), 14q32 (31%), 11q13 (28%), and 20q13.3 (28%). High-level gains (HLGs) indicative of gene amplifications were identified at 11q13 in two cases, and in one case each at 2q33-34, 3q25-29, 5p15.1-15.2, 7q21-22, 11p11.2, 12p11.2-12, and 13q34. Recurrent losses were observed only at 9p13(17.2%). In the 12 ESC cell lines, the most common sites of HLGs were 5p15.1-15.3 (four cases), 11q13 (four cases), 8q24.1-24.2 (three cases), 20q13.2-13.3 (three cases), 3q26.3 (two cases), and 7p15-22 (two cases). Less frequent HLGs (one case each) were observed at 2p16-22, 3q25, 7p12-14, 7q21-22, 9q34, 10q21, 11p11.2, 14q13-14, 14q31-32, 15q22-26, and 17p11.2. Chromosomes and chromosome arms that showed frequent losses in the cultured lines were 18q (58%), 4 (50%), 9p (50%), and 3p (42%). These findings provide evidence for a number of previously unknown genomic aberrations in ESC, suggesting target regions for positional cloning of genes relevant to carcinogenesis in the esophagus. In particular, we identified a significant amplification of the DPI gene (TFDPI), a transcription factor that forms heterodimers with E2FI, in the single primary tumor that exhibited HLG at 13q34.

Blotting, Southern↗
PubMed1999

Combined spectral karyotyping and DAPI banding analysis of chromosome abnormalities in myelodysplastic syndrome.

Spectral karyotyping (SKY) is a new molecular cytogenetic technique that allows simultaneous visualization of each chromosome in a different color. We have used SKY for comprehensive analysis of 20 myelodysplastic syndromes (MDSs) (13 primary MDSs, 3 therapy-related MDSs, and 4 acute leukemias developed from MDS, including 1 cell line established from a secondary leukemia), previously analyzed by G-banding. To locate the chromosomal breakpoints, DAPI-counterstained band images from all metaphases were transformed to G-band-like patterns. By using SKY, it was possible to identify the origin and organization of all clonal marker chromosomes (mar), as well as the origin of all abnormalities defined as additional material of unknown origin (add) or homogeneously staining regions (hsr) by G-banding. In total, SKY identified the chromosomal basis of 38 mar, add, and hsr, corrected 8 abnormalities misidentified by G-banding, and revealed 6 cryptic translocations in 5 cases. Total or partial chromosomal loss (mainly of -5/5q- and -7/7q-) is the most frequent cytogenetic abnormality in MDS. In 3 of 11 cases with -5/5q- and in 4 of 8 with -7/7q-, lost material was detected by SKY in unbalanced translocations. A total of 60 chromosomal losses were identified by G-banding in 16 cases with multiple chromosome abnormalities involving at least 3 chromosomes. For 26 of these losses (43%), SKY analysis suggested that the losses were not complete, but had been translocated to a variety of partner chromosomes. Moreover, SKY analysis revealed that a ring chromosome in a case of acute leukemia developed from MDS contained three to six segments that originated from chromosome 21 material. Fluorescence in situ hybridization showed the amplification of the AML1 gene on regions derived from chromosome 21, providing the first evidence of amplification involving this gene in MDS. Genes Chromosomes Cancer 26:336-345, 1999.

Adult↗
PubMed1999

[Detection of numerical aberrations in chromosomes by fluorescence in situ hybridization in fine needle aspirates in the preoperative diagnosis of cancer].

Fine needle aspiration (FNA) samples were obtained from 176 breast tumors suspected of malignancy, which were then subjected to conventional cytological and fluorescence in situ hybridization (FISH) analyses using the centromeric probes for chromosomes 1, 11, and 17. Histological examination revealed 157 breast cancers and 19 benign diseases (ten fibroadenomas, six intraductal papillomas, one intracystic papilloma, and two ADH). Sensitivity, specificity, and diagnostic accuracy were 85.4% 94.7%, and 86.4%, respectively, for cytology and 90.4%, 100%, and 91.5%, respectively, for FISH. These results demonstrate that FISH diagnosis of FNA samples has a diagnostic accuracy comparable to that of conventional cytology.

Biopsy, Needle↗
PubMed1998

A novel human RasGAP-like gene that maps within the prostate cancer susceptibility locus at chromosome 1q25.

We report the molecular cloning of a human cDNA that encodes a molecule having striking homology with Ras-specific GTPase-activating proteins (RasGAPs). Among previously described RasGAPs, the cDNA product is most closely related to Caenorhabditis elegans GAP-2, including a predicted coiled-coil structure near the carboxyl terminus. Expression of the cDNA in Saccharomyces cerevisiae defective in one of two RasGAPs, Ira2, complemented loss of the Ira2 function, indicating that the cDNA product functions as a RasGAP. The RasGAP-like gene is located on the human chromosome 1q25, the locus that appears to contain a hereditary prostate cancer susceptible gene, HPC1.

Amino Acid Sequence↗
PubMed1998

Molecular cloning and characterization of human caspase-activated DNase.

Caspase-activated DNase (CAD) cleaves chromosomal DNA during apoptosis. Here, we report isolation of two classes of human CAD cDNAs from a human KT-3 leukemic cell cDNA library. One class of cDNA encoded a protein comprising 338 amino acids, which showed a marked similarity to its murine counterpart. In vitro transcription and translation of this cDNA resulted in a functional CAD protein when the protein was synthesized in the presence of its inhibitor (inhibitor of CAD). The other cDNA class contained many deletions, insertions, and point mutations in the sequence corresponding to the coding region, suggesting that it is derived from a pseudogene. The functional CAD gene was localized to human chromosome 1p36.3 by fluorescent in situ hybridization. The CAD mRNA was expressed in a limited number of human tissues, including pancreas, spleen, prostate, and ovary. The expression of the CAD mRNA in human cell lines correlated with their ability to show DNA fragmentation during apoptosis. Overexpression of CAD potentiated DNA fragmentation by apoptotic stimuli in these cell lines, indicating that CAD is responsible for the apoptotic DNA degradation.

Amino Acid Sequence↗
PubMed1998

Loss of material from chromosome arm 1p during malignant progression of meningioma revealed by fluorescent in situ hybridization.

BACKGROUND: Atypical and anaplastic meningiomas tend to recur and to invade adjacent brain, bone, and skin. They also can metastasize to extracranial organs such as the lung, liver, or bone, causing death. Recent reports have indicated that allelic deletion of chromosome 1p is associated with malignant progression of meningiomas. METHODS: Cytogenetic analysis of 37 meningiomas was performed using double-target fluorescent in situ hybridization (FISH) and focusing on chromosome arm 1p. The meningioma series included 17 benign meningiomas, 11 atypical meningiomas, and 9 anaplastic meningiomas. FISH was performed with pericentromeric (1q12) and subtelomeric (1p36) DNA probes to cell nuclei prepared from surgically extirpated tumor samples. RESULTS: A high incidence of deletion of at least part of 1p was observed in 60.0% of atypical and 85.7% of anaplastic meningiomas. Furthermore, statistically significant differences were found with respect to these data between benign versus atypical/anaplastic meningiomas. In four cases both primary and recurrent tumors from the same patient also were investigated for allelic status. CONCLUSIONS: The results of the current study support the existence of tumor suppressor gene(s) on 1p associated with malignant progression of meningioma, and suggest that detection of the allelic status of chromosome 1p by FISH may assist physicians in predicting the clinical prognosis of patients affected by this type of brain tumor.

Adult↗
PubMed1998

The human chromosomal gene for necdin, a neuronal growth suppressor, in the Prader-Willi syndrome deletion region.

Necdin is a growth suppressor expressed in virtually all postmitotic neurons in the brain. The human necdin gene, NDN, is maternally imprinted and deleted in the Prader-Willi syndrome, a neurobehavioral contiguous gene disorder. Here, we isolated and characterized the human chromosomal necdin gene and its promoter region. The necdin gene is intronless, and it encodes a protein of 321 amino acid residues, four residues shorter than mouse Necdin. By fluorescence in-situ hybridization analysis, the necdin gene was localized to chromosome 15q11.2-q12 within the Prader-Willi syndrome deletion region. CpG islands were found in a region extending from the proximal 5'-flanking sequence to the protein coding region. The 5'-flanking sequence, which lacks canonical TATA and CAAT boxes, possessed a promoter activity in postmitotic neurons derived from murine embryonal carcinoma P19 cells. Methylation in vitro of HhaI CpG sites in the promoter region reduced the transcriptional activity. These results suggest that the necdin gene is silenced through methylation of the CpG island encompassing its promoter region.

Amino Acid Sequence↗
PubMed1998

Identification and characterization of a novel SH3-domain binding protein, Sab, which preferentially associates with Bruton's tyrosine kinase (BtK).

Protein interaction cloning method was used to identify a novel molecule, Sab, which binds to the SH3 domain of Bruton's tyrosine kinase (Btk), the deficient cytoplasmic tyrosine kinase in human X-linked agammaglobulinemia and murine X-linked immunodeficiency. Immunoprecipitation using the anti-Sab antibody identified the protein product of the gene as a 70 kDa molecule. While Sab does not have a proline-rich sequence, it was shown to bind to Btk through the commonly conserved structure among SH3 domains. Remarkably, Sab exhibited a high preference for binding to Btk rather than to other cytoplasmic tyrosine kinases, which suggests a unique role of Sab in the Btk signal transduction pathway.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Detection and isolation of a novel human gene located on Xp11.2-p11.4 that escapes X-inactivation using a two-dimensional DNA mapping method.

Using a two-dimensional DNA mapping method, we detected four NotI restriction sites that escape chromosome X-specific methylation in humans. Two genes corresponding to two of these sites that lie in the region of Xp11.2-p11.4 were cloned and their properties studied. One of the genes matched a known gene, but the other, termed EXLM1, is novel and is predominantly expressed in cultured lymphocytes and skeletal muscle.

Amino Acid Sequence↗
PubMed1998

A novel myeloid cell line, Marimo, derived from therapy-related acute myeloid leukemia during treatment of essential thrombocythemia: consistent chromosomal abnormalities and temporary C-MYC gene amplification.

A novel myeloid leukemia cell line, Marimo, was established from bone marrow cells of a patient with secondary acute myeloid leukemia (AML) that had developed during the treatment of essential thrombocythemia (ET) with busulfan. Karyotype at the ET phase was 46,XX,der(15)t(1;15) (q23;p12-13), but at the blastic phase changed to 44,XX,-5,del(8)(q22), add(17)(p11),+18, psu dic(18;9) (q23;p21) x 2 lacking t(1;15). In Marimo cells, C-MYC gene was temporarily amplified by double-minutes (dmin) but disappeared at 33 months, whereas t(10;14;11)(q22;q32;q13) and t(10;14)(q22;q32) were added in vitro psu dic(18;9) x 2 and add(17)(p11) were consistently found throughout the culture. These results suggest that this AML clone is not derived from ET but rather is therapy-related.

Cell Line↗
PubMed1998

Identification of CpG islands hypermethylated in human lung cancer by the arbitrarily primed-PCR method.

DNA hypermethylation is believed to be involved in human carcinogenesis, since it suppresses the transcription of defined genes and is associated with chromosomal instability. In this study, we identified CpG islands that are hypermethylated in human lung cancer by a modified arbitrarily primed-polymerase chain reaction method using genomic DNAs digested with a methylation-sensitive restriction enzyme, HpaII, as templates. When we analyzed genomic DNAs from normal lung tissues and non-small cell lung carcinoma cell lines using three arbitrary primers, three DNA fragments were amplified from lung cancer DNAs but not from normal lung DNAs. Restriction mapping and Southern blot analysis revealed that all of these bands were amplified from CpG islands that were hypermethylated in the lung cancer cell lines. These islands were mapped to chromosomes 4q34, 10q26 and 17p13.1-p13.2, respectively, and these chromosomal regions were also hypermethylated in a subset of primary lung tumors in vivo. Thus, diverse chromosomal regions are hypermethylated in lung cancer cells. The results also indicate that this method is simple and effective for screening of CpG islands that are hypermethylated in cancer cells.

Carcinoma↗
PubMed1998

Identification of amplified DNA sequences on double minute chromosomes in a leukemic cell line KY821 by means of spectral karyotyping and comparative genomic hybridization.

Double minute chromosomes (dmin) are cytogenetic hallmarks of amplified genes. Using spectral karyotyping (SKY) and comparative genomic hybridization (CGH), we identified the origin of amplified DNA in a leukemic cell line, KY821, that harbors numerous dmin. The SKY revealed that the DNA sequences of dmin are derived from materials of chromosome 8, and CGH showed a high degree of overrepresentation only at 8q22-24, indicating that in KY821 only chromosomal material of 8q22-24, containing MYC, is amplified in dmin. An approach combining SKY with CGH should facilitate efforts to identify novel chromosomal regions of gene amplification and contribute information about genetic lesions that underly neoplastic tumors.

DNA, Neoplasm↗