The SHN mouse strain, established in Japan independently from other mammary tumor-prone strains, is known to have a very high incidence of early-onset mammary tumors. In this study, we demonstrate that exogenous mouse mammary tumor virus (MMTV) plays a crucial role in early-onset mammary tumorigenesis in this strain. We subsequently isolated MMTV RNA from a mammary tumor of an SHN female mouse, reverse transcribed it, and amplified a 1.2-kb coding region of the long terminal repeat (LTR) by use of the polymerase chain reaction. The products were then subcloned into a pUC18 vector. Six clones were obtained, and their nucleotide sequences were determined. Nucleotide sequences of the six cloned LTRs indicated that two MMTVs are transcribed in the tumor. Both of them had point mutations and were different from known LTR sequences. Both LTRs had a potential open reading frame encoding 320 amino acids. The amino acid variabilities were predominantly between positions 280 and 320 codons when compared with deduced open reading frames. In contrast, only a few point mutations were detected in the regulatory area that contains five glucocorticoid elements, the nuclear factor-1 binding sites, the octamer consensus sequence, and the TATA box. Because point mutations occur more predominantly between positions 280 and 320, it is possible that mutations in this area endow MMTV with beneficial functions for propagation through mutational selection during tumorigenesis.

Animals↗

PubMed1994

Dysphagia caused by a large pulmonary bulla.

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Deglutition Disorders↗

PubMed1993

Mutations of the p53 gene as a predictor of poor prognosis in patients with non-small-cell lung cancer.

BACKGROUND: Inactivation of the p53 tumor suppressor gene (also known as TP53) through a point mutation and/or loss of heterozygosity is one of the most common genetic changes found in various types of human tumors. PURPOSE: Our purpose was to investigate the relationship between the presence of p53 gene mutations and survival of patients with non-small-cell lung cancer (NSCLC) of all stages who underwent surgery with preoperative curative intent as a routine therapeutic intervention. The prognostic significance of factors like sex, age, tumor histology, and the stage of the disease was also evaluated. METHODS: We analyzed 120 tumor specimens from patients with histologically confirmed NSCLC for p53 mutations occurring in exons 5 through 8 by polymerase chain reaction-single-strand conformation polymorphism assay of genomic DNA. Univariate and multivariate analyses were performed to assess the association between p53 mutations and the survival of the NSCLC patients. RESULTS: Fifty-one (43%) of 120 tumor specimens showed p53 mutations. Overall, the p53 mutations did not correlate with sex, age, or the clinical stage of the disease but showed frequent association with tumors of squamous cell histology. Univariate analysis revealed that the patients with p53 mutations survived for a significantly shorter period of time after surgery than those without the mutations (P = .0100, logrank test). The presence of p53 mutations was a significant prognostic factor in the patients with advanced disease (stages IIIA through IV) (P = .0091) but not in those with early disease (stages I and II) (P = .2837). Multivariate analysis using the Cox proportional hazards model found independent prognostic significance for p53 mutations (hazards ratio [HR] = 1.84; P = .018) and advanced disease stage (HR = 2.20; P = .003). The model also predicted the lower risk for female patients (HR = 0.51; P = .040). CONCLUSION: The occurrence of p53 mutations in some NSCLC tumors may be independently associated with a shortened overall survival and may be of somewhat more prognostic significance in patients with advanced stage than in those with early stage of the disease. IMPLICATION: Detection of p53 mutations may help in the selection of NSCLC patients suitable for appropriate investigational therapeutic strategies in view of improving their survival and quality of life.

Aged↗

PubMed1993

Low-temperature-dependent expression of a rice gene encoding a protein with a leucine-zipper motif.

We have isolated from rice suspension cells three non-sequence-related cDNAs the expression of which is markedly induced by low, non-freezing temperature. Here we further characterize one of the cDNA clones, lip19. Expression of lip19 is positively regulated by low temperature, but not affected by high (40 degrees C) temperature. Sequencing and primer extension analyses showed that lip19 has a long (552 bp) 5' non-coding sequence followed by a single open reading frame specifying a protein of 148 amino acids. The deduced amino acid sequence of the protein, Lip19, shows at its amino-terminus a conserved basic region followed by a "leucine-zipper" domain. The reported sequence most similar to Lip19 is maize OCSBF-1, which is a bZip-type DNA binding protein. The possibility is suggested that Lip19 is a transcriptional factor that is positively controlled by low temperature.

Amino Acid Sequence↗

PubMed1993

Identification of the purA gene encoding adenylosuccinate synthetase in Thiobacillus ferrooxidans.

The purA gene of Thiobacillus ferrooxidans encoding adenylosuccinate synthetase [EC 6.3.4.4] was identified in the upstream region of the iro gene encoding Fe(II)-oxidase (J. Biol. Chem 267:11242-11247, 1992). The purA gene consisted of 1290 base-pairs, which translated into a 29-amino-acid protein. The gene is functionally active, because it is able to complement an Escherichia coli purA-deficient strain. The deduced gene product has a high degree (60.9%) of sequence identity with that (432 aa) of E. coli purA gene, and both the products share GDEGKGK-DETG-TKLD sequences which are supposed to be GTP-binding domain. The downstream region of the iro gene contained another open-reading frame (ORF) of 1218 bp, and this showed high homology (56.6% over 249 bp) with E. coli ORF-II, which is found as a second ORF and truncated form in the downstream region of the purA gene. Comparison of the gene organization in the flanking region of purA gene between T. ferrooxidans and E. coli is also described.

Adenylosuccinate Synthase↗

PubMed1993

Specific binding of Thiobacillus ferrooxidans RbcR to the intergenic sequence between the rbc operon and the rbcR gene.

The presence of two sets (rbcL1-rbcS1 and rbcL2-rbcS2) of rbc operons has been demonstrated in Thiobacillus ferrooxidans Fe1 (T. Kusano, T. Takeshima, C. Inoue, and K. Sugawara, J. Bacteriol. 173:7313-7323, 1991). A possible regulatory gene, rbcR, 930 bp long and possibly translated into a 309-amino-acid protein, was found upstream from the rbcL1 gene as a single copy. The gene is located divergently to rbcL1 with a 144-bp intergenic sequence. As in the cases of the Chromatium vinosum RbcR and Alcaligenes eutrophus CfxR, T. ferrooxidans RbcR is thought to be a new member of the LysR family, and these proteins share 46.5 and 42.8% identity, respectively. Gel mobility shift assays showed that T. ferrooxidans RbcR, produced in Escherichia coli, binds specifically to the intergenic sequence between rbcL1 and rbcR. Footprinting and site-directed mutagenesis experiments further demonstrated that RbcR binds to overlapping promoter elements of the rbcR and rbcL1 genes. The above data strongly support the participation of RbcR in regulation of the rbcL1-rbcS1 operon and the rbcR gene in T. ferrooxidans.

Amino Acid Sequence↗

PubMed1993

Intratumoral heterogeneity of DNA ploidy and regional differences in epidermal growth factor and epidermal growth factor receptor of esophageal carcinoma.

Intratumoral regional differences in DNA ploidy patterns, and expression of epidermal growth factor (EGF) and EGF receptor (EGF-R) were studied to evaluate the biological and clinical significance of intratumoral DNA heterogeneity in 23 cases of esophageal carcinoma. Multiple specimens were subjected to histologic grading of carcinoma, DNA analysis and immunohistochemistry. DNA heterogeneity was found in 34.8% of the cases. Expression of EGF and EGF-R within a single tumor was observed in 69.6% and 73.9% of the lesions examined, respectively. A positive correlation was noted between the expression of EGF and that of the EGF-R. EGF expression showed positive correlation with the DNA index, but not with the proliferative index. There was no relationship between DNA heterogeneity and the degree of histopathological differentiation of carcinoma. Cases with DNA heterogeneity showed better prognosis than those with DNA homogeneity. The present study suggests that esophageal carcinoma consists of carcinoma cells with intratumoral regional polymorphism and variable types of clones. Furthermore, the autocrine mechanism of EGF and EGF-R could be one of the contributory factors on the development of DNA abnormalities during tumor proliferation.

Adult↗

PubMed1992

Molecular cloning of the gene encoding Thiobacillus ferrooxidans Fe(II) oxidase. High homology of the gene product with HiPIP.

The amino-terminal sequence of Thiobacillus ferrooxidans Fe(II) oxidase (linked to cytochrome c552) was determined, and the iro gene that encodes this enzyme was cloned using degenerate oligonucleotides as a probe. The DNA sequence of a region (856 base pairs) which encompasses the iro gene revealed that the enzyme was encoded by a 273-base pair open reading frame and consists of 90 amino acids, including a possible 37-residue signal sequence. The iro gene seems to be transcribed independently of any other gene because the transcriptional products are 0.45 and 0.6 kilobases in size. Current protein databases revealed that the iro gene product is a new member of the high redox potential iron sulfur proteins, which generally function in electron transport but do not show enzymatic activity.

Amino Acid Sequence↗

PubMed1992

Nucleotide sequence of a rice rab16 homologue gene.

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Abscisic Acid↗

PubMed1992

Postoperative pyothorax.

Twenty-five cases of pyothorax occurred in a series of 1281 thoracotomies. Almost all cases of pyothorax without bronchopleural fistula were successfully treated by closed drainage and irrigation alone. On the other hand, patients with pyothorax and fistula who were treated only with closed drainage almost all had a poor outcome. When pyothorax with fistula was treated by closed drainage and irrigation followed by further procedures such as open window thoracostomy, muscle plombage and/or omentopexy, treatment was successful. It is concluded that pyothorax without fistula may be cured by closed drainage and irrigation alone, but that pyothorax with fistula requires operative intervention such as open window thoracostomy or omental flap as soon as possible.

Adolescent↗

PubMed1992

Rice dwarf phytoreovirus segment S12 transcript is tricistronic in vitro.

Sequence analysis revealed that rice dwarf phytoreovirus segment S12 is 1066 nucleotides long with a small out-of-phase, overlapping open reading frame (ORF) as well as a major ORF. The large ORF (positions 42 to 980) encodes 312 amino acids, while the small one (bases 313 to 591) encodes 92 amino acids with an additional in-frame AUG codon (positions 337-339) 24 nucleotides downstream from the first one. Transcripts from a full-length cDNA directed the in vitro synthesis of three polypeptides of 33 (considered to be translated from the long ORF), 8, and 7 kDa. Alteration of each of the two ATG codons on the small ORF demonstrated their involvement in the generation of the 8- and 7-kDa polypeptides. Although it is still unknown whether these proteins are expressed in vivo, the small ORF is shown to be conserved in S9s of two other members of the genus Phytoreovirus, rice gall dwarf virus and wound tumor virus, suggesting its common, important function.

Amino Acid Sequence↗

PubMed1992

Molecular analysis of rice dwarf phytoreovirus segment S1: interviral homology of the putative RNA-dependent RNA polymerase between plant- and animal-infecting reoviruses.

We have determined the complete nucleotide sequence of the largest segment S1 of rice dwarf phytoreovirus (RDV), a member of the family Reoviridae. S1 is 4423 nucleotides long with a segment-specific inverted repeat located adjacent to the conserved termini (5'GGCAAA---UGAU3'). A major open reading frame (bases 36 to 4367) on the S1 plus strand, which is preceded by a minicistron (bases 6 to 29), encodes the polypeptide (P1) consisting of 1444 amino acids with a M(r) of 164, 142. The sense-strand transcript derived from the full-length S1 cDNA, the minicistron of which was abolished, directed the synthesis of a polypeptide of 170 kDa in addition to smaller polypeptides in wheat germ extracts, and the 170-kDa product comigrated with the minor core protein in SDS-polyacrylamide gel. Thus, P1 is assumed to be localized in the viral core particle. The consensus sequence element conserved in RNA-dependent RNA polymerase is observed in the P1 amino acid sequence predicted from the nucleotide sequence. Based on the dendrogram established from the sequence alignment around the polymerase module region, and sequence identity within the alignment, P1 of plant-infecting RDV was evolutionarily compared with VP1, lambda 3, and VP1 of three other animal-infecting members of the family, rota-, reo-, and bluetongue viruses. Consequently, RDV S1 was shown to be more closely related to the rotavirus gene segment 1, in terms of molecular evolution, than the animal-infecting members are to one another.

Amino Acid Sequence↗

PubMed1992

Diaphragmatic cyst with elevated level of serum tissue polypeptide antigen.

A 58-year-old woman with a mesothelial cyst of the diaphragm showed high level of serum Tissue Polypeptide Antigen (TPA) and cyst fluid TPA. Mesothelial cells of the cyst may excrete TPA and TPA was accumulated in the cysts. The measurement of tumor marker such as TPA of the serum or of the content of the cyst is useful in observation of the clinical course.

Biomarkers, Tumor↗