Initiating sequences in exercise induced idiopathic ventricular tachycardia of left bundle branch-like morphology

The human gene set was originally identified as a component of the set-can fusion gene produced by a somatic translocation event in a case of acute undifferentiated leukemia. In the developing kidney, set was highly expressed in the zone of nephron morphogenesis. Recently, SET was shown to be a potent and specific inhibitor of protein phosphatase 2A, a family of major serine/threonine phosphatases involved in regulating cell proliferation and differentiation. The current study sought to define further the role of SET in the regulation of renal cell proliferation and tumorigenesis. The mRNA encoding SET was expressed at much higher levels in transformed human and rodent cell lines than in cultured renal epithelial and primary endothelial cells. Consistent with a role for SET in cell proliferation, set mRNA expression was markedly reduced in cells rendered quiescent by serum starvation, contact inhibition, or differentiation. Previous findings during renal development were extended by demonstrating that SET protein expression is also much greater in developing rat and human kidney than in fully differentiated, mature kidney. Finally, high levels of set mRNA and SET protein expression were found in Wilms' tumor, but not in renal cell carcinoma, adult polycystic kidney disease or in transitional cell carcinoma.     

Detection of mitochondrial genome depletion by a novel cDNA in renal cell carcinoma

A cDNA isolated by a subtractive hybridization procedure detected loss of mtDNA and the mRNA coding for NADH dehydrogenase subunit 3 in 8 of 13 tumor kidney tissues obtained from patients with renal cell carcinoma. Sequencing revealed a stretch of nucleotides homologous to the mitochondrial NADH dehydrogenase subunit 3 gene in the middle of the cDNA. The depletion phenomenon was also observed in five of six renal carcinoma cell lines. In the case of a benign renal oncocytoma, however, the mtDNA content was increased 200% more than that of the adjacent normal tissue. The frequency with which this phenomenon occurs in renal cell carcinomas, but not in other types of cancers, suggests that this may be an important phenotype associated with renal cell neoplastic transformation. However, the absence of any structural alterations within the mitochondrial genome suggests that the depletion may be a secondary event associated with the oncogenic transformation process.     

Human NELL-1 expressed in unilateral coronal synostosis

Surgical correction of unilateral coronal synostosis offers a unique opportunity to examine the molecular differences between an abnormal and a normal cranial suture. We isolated and identified a cDNA fragment whose expression was up-regulated in the premature fusing and fused coronal sutures, as compared with normal coronal sutures. The nucleotide sequence of the full-length cDNA of this gene, human NELL-1, has approximately 61% homology with the chicken Nel gene. Both chicken Nel and human NELL-1 are comprised of six epidermal growth factor-like repeats. The human NELL-1 messages were localized primarily in the mesenchymal cells and osteoblasts at the osteogenic front, along the parasutural bone margins, and within the condensing mesenchymal cells of newly formed bone in sites of premature sutural fusion. Human multiorgan tissue mRNA blot showed that NELL-1 was specifically expressed in fetal brain but not in fetal kidney, liver, or lung. We also showed that Nell-1 was expressed in rat calvarial osteoprogenitor cells and was largely absent in rat tibiae and fibroblast cell cultures. In conclusion, our data suggest that the NELL-1 gene is preferentially expressed in cranial intramembranous bone and neural tissue (both of neural crest cell origin) and is up-regulated during unilateral premature closure of the coronal suture. The precise role of this gene is unknown.     

Indication of medical abortion in cases of fetal abnormalities diagnosed in utero

OBJECTIVE: To search the novel gene related to human hepatoma. METHODS: Northern blot analysis was used to isolate from EST (expressed sequence tags) clones a cDNA fragment differentially expressed in hepatocellular carcinoma versus its surrounding noncancerous hepatic tissue. Human fetal liver cDNA library was screened with EST fragment probe. RESULTS: Northern blot analysis showed that EST clone F9391 expressed at high level in all the 6 hepatocellular carcinoma samples but low level in the surrounding noncancerous hepatic tissues and 2 normal liver tissues. In further screening of human fetal liver cDNA library, we obtained a positive clone named FL6. Nucleotide sequencing indicated that FL6 contained 1464 base pairs and the matched DNA sequence was not found in the gene data bases (EMBL 96.6). Northern blot analysis of various fetus tissues with FL6 probe showed a high level expression in lung, small intestine, skin and placenta, middle level expression in liver, stomach, colon and muscle but low level expression in brain, thyroid, thymus, heart, kidney, pancreas and bladder. CONCLUSION: The results suggested that FL6 gene related to cell proliferation and may play an important role in the process of oncogenesis.     

Increased susceptibility to in vitro transformation of cells carrying the Eker tumor susceptibility mutation

Rats carrying the Eker tumor susceptibility mutation are genetically predisposed to renal cell carcinoma. Rats heterozygous for the Eker mutation (Eker carriers) develop multiple bilateral renal cell carcinomas by the age of 1 year. Using an in vitro rat kidney epithelial (RKE) transformation assay developed in our laboratory, proximal tubule cells derived from known Eker rat carriers (+/ek) and non-carriers (+/+) were exposed to the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), to determine if cells derived from Eker carriers were more susceptible to in vitro transformation than cells derived from non-carrier animals. The percent transformation frequency following MNNG treatment was 7.5-fold higher in cells derived from carrier animals when compared to cells from non-carrier animals. This increased susceptibility to transformation due to inheritance of the Eker mutation is consistent with a predisposition resulting from inactivation of a tumor suppressor gene. The increased susceptibility of kidney epithelial cells carrying the Eker mutation may prove useful in the further development of the RKE transformation assay as a sensitive tool to identify potential renal carcinogens. In addition, because transformation frequency in the RKE assay measures a very early step in multistage transformation, these results also suggest that alterations (by Loss of Heterozygosity or mutation) at the Eker tumor susceptibility locus are an early event in the development of renal tumors in the rat.     

Blocked negative selection of developing T cells in mice expressing the baculovirus p35 caspase inhibitor

Despite advances in characterizing the pathophysiology and genetics of pituitary tumors, molecular mechanisms of their pathogenesis are poorly understood. Recently, we isolated a transforming gene [pituitary tumor-transforming gene (PTTG)] from rat pituitary tumor cells. Here we describe the cloning of human PTTG, which is located on chromosome 5q33 and shares striking sequence homology with its rat counterpart. Northern analysis revealed PTTG expression in normal adult testis, thymus, colon, small intestine, brain, lung, and fetal liver, but most abundant levels of PTTG mRNA were observed in several carcinoma cell lines. Stable transfection of NIH 3T3 cells with human PTTG cDNA caused anchorage-independent transformation in vitro and induced in vivo tumor formation when transfectants were injected into athymic mice. Overexpression of PTTG in transfected NIH 3T3 cells also stimulated expression and secretion of basic fibroblast growth factor, a human pituitary tumor growth-regulating factor. A proline-rich region, which contains two PXXP motifs for the SH3 domain-binding site, was detected in the PTTG protein sequence. When these proline residues were changed by site-directed mutagenesis, PTTG in vitro transforming and in vivo tumor-inducing activity, as well as stimulation of basic fibroblast growth factor, was abrogated. These results indicate that human PTTG, a novel oncogene, may function through SH3-mediated signal transduction pathways and activation of growth factor(s).     

The LSP1 gene is expressed in cultured normal and transformed mouse macrophages

The mouse LSP1 protein is an F-actin binding protein initially isolated as a cDNA from the BALB/c pre-B cell line 220.2. Its expression pattern is highly restricted. Only lymphocytes and lymphoma cell lines were reported to express LSP1. Non-lymphoid cell lines or normal mouse tissues such as brain, lung, liver, skeletal muscle, kidney or testis do not express LSP1. Here we report that mouse macrophage cell lines also express LSP1 mRNA and protein. DNA sequence analysis shows that the coding sequence of LSP1 RNA expressed in the macrophage cell line P388D1 is identical to the sequence of LSP1 RNA from the pre-B cell line 220.2. To determine the expression of LSP1 RNA in normal macrophages derived from fetal liver and adult bone marrow and in other hematopoietic cells we used a recently described technique to make representative amplified polyA cDNA samples from small numbers of cells or isolated hematopoietic colonies. Analysis of these cDNA samples with an LSP1 cDNA probe showed that eight of nine macrophage samples expressed LSP1 RNA. One of two neutrophil samples but none of eight other non-lymphoid colonies was positive for LSP1 RNA. From these results it appears that the expression of LSP1 RNA in the hematopoietic system is restricted to the lymphocyte, macrophage and neutrophil lineages.     

Molecular cloning of a novel cytokine cDNA encoding the ninth member of the fibroblast growth factor family, which has a unique secretion property

Glia-activating factor (GAF) is a novel heparin-binding growth factor purified from the culture supernatant of a human glioma cell line. It shows a spectrum of activity slightly different from those of other known growth factors. We have isolated the cDNA which encodes human GAF. A homology search revealed that GAF would be the ninth member of the FGF family, and we therefore call it FGF-9. The human FGF-9 cDNA cloned by using oligonucleotide probes encoded a polypeptide consisting of 208 amino acids. Sequence similarity to other members of the FGF family was estimated to be around 30%. Two cysteine residues and other consensus sequences in family members were also well conserved in the FGF-9 sequence. FGF-9 was found to have no typical signal sequence in its N terminus like those in acidic FGF and basic FGF. Acidic FGF and basic FGF are known not to be secreted from cells in a conventional manner. However, FGF-9 was found to be secreted from cells after synthesis despite its lack of a typical signal sequence. It could be detected exclusively in the culture medium of cDNA-transfected COS cells. The amino acid sequence of proteins purified from culture supernatant of the CHO cell line, which was cDNA transfected and selected as a high producer of FGF-9, showed that no peptides were cleaved from the N terminus except the initiation methionine. The rat FGF-9 cDNA was also cloned, and the structural analysis indicated that the PGF-9 gene is highly conserved. Expression of the FGF-9 gene could be detected in the brain and kidney of the adult rat. Restricted gene expression in organs and the unique secretion nature of the protein suggest that FGF-9 plays a physiological role which differs from those of well-characterized acidic FGF and basic FGF.