Isolation and mapping of karyopherin alpha 3 (KPNA3), a human gene that is highly homologous to genes encoding Xenopus importin, yeast SRP1 and human RCH1.

From a human fetal-brain cDNA library, we isolated and characterized a novel gene (KPNA3) encoding a protein highly homologous to certain nuclear transport proteins of Xenopus and human. The complete cDNA clone, designated karyopherin alpha 3, contained an open reading frame of 1,563 nucleotides encoding 521 amino acids. The predicted amino acid sequence showed 48%, 45% and 48% identity with Xenopus importin, yeast SRP1 and human RCH1, respectively. The similarities among these proteins suggest that karyopherin alpha 3 may be involved in the nuclear transport system. Eight repeats of the arm motif were well conserved among these proteins. The N-terminal region of the predicted karyopherin alpha 3 product was highly basic and the C-terminal region was strongly acidic. A 4.3-kb transcript was expressed in all adult human tissues examined by Northern blotting. The cDNA clone was assigned to chromosome band 13q14.3 by fluorescence in situ hybridization.


Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily.

A full-length cDNA homologous to RAB7, a member of the RAB-related GTP-binding protein subfamily, was isolated from a human placenta cDNA library. This cDNA, designated RAB7L1, has an open reading frame of 609 nucleotides encoding 203 amino acids. Northern analysis showed that the mRNA is ubiquitously expressed in human tissues, although signal intensities were different among the various organs examined. This gene was located on chromosome band 1q32 by fluorescence in situ hybridization.


Mutations in the BRCA2 gene in hepatocellular carcinomas.

To investigate whether the BRCA2 gene plays a role in carcinogenesis of hepatocellular carcinomas or pancreatic cancers in view of frequent losses of heterozygosity on chromosome 13q12-13 in those tumors, we screened the entire coding region of this gene for mutations in 60 hepatocellular carcinomas and 36 pancreatic cancers. No alteration was found in any of the pancreatic cancers examined, but three mutations were identified in hepatocellular carcinomas; one was a 6-bp somatic deletion within intron 6. The other two mutations we identified in hepatocellular carcinomas were missense mutations in the germ line, although all BRCA2 mutations thus far detected in patients with familial breast cancers likewise have been deletions. None of 194 other patients with cancers or 44 normal controls exhibited either mutation. Combined with our demonstration of BRCA2 expression in adult liver tissue, the evidence implies that inactivation of BRCA2 may play some role in development or progression of hepatocellular carcinoma and might predispose carriers of mutant alleles to liver malignancies.


Mutation analysis in the BRCA2 gene in primary breast cancers

Breast cancer, one of the most common and deleterious of all diseases affecting women, occurs in hereditary and sporadic forms. Hereditary breast cancers are genetically heterogeneous; susceptibility is variously attributable to germline mutations in the BRCA1 (ref. 1), BRCA2 (ref. 2), TP53 (ref. 3) or ataxia telangiectasia (ATM) genes, each of which is considered to be a tumour suppressor. Recently a number of germline mutations in the BRCA2 gene have been identified in families prone to breast cancer. We screened 100 primary breast cancers from Japanese patients for BRCA2 mutations, using PCR-SSCP. We found two germline mutations and one somatic mutation in our patient group. One of the germline mutations was an insertion of an Alu element into exon 22, which resulted in alternative splicing that skipped exon 22. The presence of a 64-bp polyadenylate tract and evidence for an 8-bp target-site duplication of the inserted DNA implied that the retrotransposal insertion of a transcriptionally active Alu element caused this event. Our results indicate that somatic BRCA2 mutations, like somatic mutations in the BRCA1 gene, are very rare in primary breast cancers.


Mutations in the BRCA1 gene in Japanese breast cancer patients.

Predisposing germline mutations in the BRCA1 gene were identified recently in families with 17 q-linked breast and ovarian cancers. Using single-strand conformation polymorphism (SSCP) analysis, we examined primary breast cancers for mutations in coding exons of BRCA1 in a panel of 103 patients, of whom all either represented early-onset cases (< 35 of age), were members of multiply-affected families, and/or had developed bilateral breast cancers. Mutations were detected in tumors from four patients, all of whom had developed breast cancers bilaterally: a frame-shift due to a 2-bp deletion at codon 797; a nonsense mutation at codon 1214; and two missense mutations, one at codon 271 leading to Val-->Met substitution, and the other at codon 1150 leading to Pro-->Ser substitution. In each case the same mutation was present in constitutional DNA. The mean age of onset was 49 years among the Japanese carriers of BRCA1 mutations identified in this study, in contrast to the mean age of 35 observed among carriers of BRCA1 mutations in a similar U.S. study (Futreal et al., 1994). The evidence reported here supports a rather limited role of BRCA1 in breast carcinogenesis.


Cloning, expression, and chromosome mapping of adducin-(alpha) like 1 (ADDL1), a human cDNA highly homologous to human erythrocyte adducin


Cloning and characterization of two novel human cDNAs (NELL1 and NELL2) encoding proteins with six EGF-like repeats


Association of genetic alterations on chromosome 17 and loss of hormone receptors in breast cancer.

To investigate possible relationships between genetic alterations and hormonal deregulation during breast cancer development and/or progression, we examined 616 primary breast cancers for loss of heterozygosity (LOH) at chromosomal regions 16q24, 17p13.3 and 17q21, and for amplifications of the ERBB2 and c-MYC loci. A comparison of oestrogen receptor (ER) and progesterone receptor (PgR) status in tumour cells with data concerning these genetic alterations revealed that LOH at 17q21 was significantly correlated with absence of oestrogen receptors (ER) (P < 0.0003) or progesterone receptors (PgR) (P < 0.0001), and with the absence of both (P < 0.0001). Similarly, a significant association was observed between amplification of ERBB2 and the absence of either ER or PgR. LOH at 17p13.3 was associated with the absence of PgR (P < 0.01). These data suggest a possible relationship between specific genetic changes on chromosome 17 and hormonal deregulation in the progression of breast cancer.


Human metalloprotease/disintegrin-like (MDC) gene: exon-intron organization and alternative splicing.

A recently identified gene encoding a metalloprotease-like, disintegrin-like, cysteine-rich protein (MDC) represents a candidate tumor suppressor gene for human breast cancer based on its location within a minimal region of chromosome 17q21 previously defined by tumor deletion mapping. The work reported here has shown that the MDC gene consists of 28 exons interrupted by relatively short introns, most of them 67 bp to 5 kb in length. We have identified two forms of transcripts generated by alternative splicing. The more abundant form encodes a protein of 769 amino acids; the other, a previously described cDNA, encodes 524 amino acids. Exons 1a, 1b, 1c, 1d, and 2-7 encode a proprotein domain; exons 7-13, a metalloprotease-like domain; exons 14-17, a disintegrin domain; exons 18-22, a cysteine-rich domain, including an epidermal growth factor (EGF)-like repeat domain within exons 21 and 22; exon 23, a transmembrane domain; and exons 24 and 25, a short cytoplasmic domain. These results show that human MDC contains a mosaic of exons capable of encoding several functional domains.


Biochemical characterization of rice (Oryza sativa L.) mutants defective or low in nitrate reduction


Detailed analysis of loss of heterozygosity on chromosome band 17p13 in breast carcinoma on the basis of a high-resolution physical map with 29 markers.

We have constructed a physical map of chromosome band 17p13, using 29 markers that had been localized to 17p13 by means of fluorescence in situ hybridization (FISH) and analysis by pulsed-field gel electrophoresis (PFGE). The map spans nearly 8 Mb of genomic DNA, and the estimated average distance between each marker is roughly 290 kb. The p13 band of chromosome 17 is thought to contain a putative tumor suppressor gene in addition and distal to TP53. Deletion mapping in a large number of breast carcinomas indicated that the tumor suppressor gene lies between the loci defined by cC117-708 (D17S878) and p144D6 (D17S34), which are an estimated 7 Mb apart. Our results should contribute to construction of a contig map of chromosome band 17p13 with cosmid and/or YAC (yeast artificial chromosome) clones, and to isolation of the putative tumor suppressor gene.


Detailed analysis of heterozygosity on chromosome band 17p13 in breast carcinoma on the basis of a high-resolution physical map with 29 markers


Genetic studies of 457 breast cancers. Clinicopathologic parameters compared with genetic alterations.


A novel metalloprotease/ disintegrin-like gene at 17q21.3 is somatically rearranged in two primary breast cancers

From chromosomal region 17q21.3, where a tumour suppressor gene(s) for breast and ovarian cancers is thought to be present, we have isolated a novel gene from a cosmid clone that revealed somatic rearrangements in two breast cancers. The gene (MDC) encodes a 524-amino acid metalloprotease-like, disintegrin-like and cysteine-rich protein with sequence similarity to members of the snake-venom metalloprotease/disintegrin family and guinea-pig sperm-surface protein PH-30. These proteins have been implicated in cell-cell or cell-extracellular matrix interactions. Rearrangements in both tumours involve multiple exons and disrupt the coding region of the new MDC.


Mutants with low nitrate reductase activity selected from seedlings expressing nitrogen deficiency symptoms in rice (Oryza sativa L.)


Characterization of a rice (Oryza sativa L.) mutant deficient in the heme domain of nitrate reductase


Screening for nitrate reductase deficient mutants in rice (Oryza sativa L.)


Sulfoxide-mediated Cys-Trp-selective bioconjugation that enables protein labeling and peptide heterodimerization


Development of anti-cancer peptide based on prohibitin 2