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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.  相似文献   

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A human insulinoma cDNA library was constructed in the expression plasmid vector pUEX1. The clone pUEX1Ins12 was selected by means of hybridization with an insulin probe. It codes for full size amino acid sequence preproinsulin. The bacterial strain pUEX3Ins8 producing proinsulin as beta-galactosidase fusion protein was obtained for the use of recombinant protein as an antigen in an ELISA to detect serum antibodies in subjects with IDDM. Recombinant clones containing the middle, N- and C-terminal domains of the GAD65, the major autoantigen in IDDM, were constructed in pVEX1. These clones may become important tools to study the nature of GAD autoreactivity in IDDM. The clone pHICEO.9 was selected from the human insulinoma cDNA library by immunoscreening with total human insulinoma protein antibodies. This clone expresses the C-terminal fragment of human cholesterol esterase/lipase containing its antigenic determinant and can be used for blood lipase determination. Four clones containing cDNA inserts (0.47-1.42 kb) without any significant homologies to the known sequences in the Gene Bank were obtained by means of statistic selection.  相似文献   

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The strategy of isolating the band-specific expression fragments from a probe pool generated by human chromosome microdissection was reported. A chromosome 14q24.3 band-specific single copy DNA pool was constructed based on this probe pool. Using total DNA of the pool as probe to hybridize the human marrow cDNA library, 68 primary positive clones were selected from 5 x 10(5) cDNA clones. Among these primary clones, 32 secondary clones were obtained after second-round screening and designed as cFD14-1-32. Finally, 24 band-specific expression fragments were identified from these 32 positive clones by DNA hybridization. Those band-specific clones can hybridize to both 14q24.3 DNA and human genomic DNA but can't hybridize to 17q11-12 DNA. Partial sequences of 13 fragments of them were sequenced and identified as novel cDNA sequences, and these sequences were proved to have some homology with known genes in NCBI database. Analysis of expression spectrum of cFD14-1 suggested that the cDNA fragments thus obtained should be used to isolate the genes can not been cloned in 14q24.3 region.  相似文献   

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A lambda ZAP II cDNA library was constructed by cloning cDNA prepared from a high molecular weight double-stranded RNA (dsRNA, ca. 18 kb) isolated from grapevine leafroll associated closterovirus-3 (GLRaV-3) infected tissues. This cDNA library was immuno-screened with GLRaV-3 coat protein specific polyclonal and monoclonal antibodies and three immuno-positive clones were identified. Analysis of nucleotide sequences from these clones revealed an open reading frame (ORF) which was truncated at the 3' end; the remainder of this ORF was obtained by sequencing a fourth clone that overlapped with one of the immunopositive clones. A total of 2028 bp was sequenced. The putative GLRaV-3 coat protein ORF, 939 bp, encodes a protein (referred to as p35) with a calculated M(r) of 34866. Multiple alignment of the p35 amino acid sequence with coat protein sequences from other closteroviruses revealed that the consensus amino acid residues (R and D) of filamentous plant viruses are preserved in the expected locations. The GLRaV-3 coat protein gene was then engineered for sense and antisense expression in transgenic plants. Transgenic Nicotiana benthamiana plants that contain the sense GLRaV-3 coat protein gene produced a 35 kDa protein that reacted with GLRaV-3 antibody in Western blot.  相似文献   

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Fatty acid uptake is partly controlled by the FATP gene family, of which at least five members are known in mice. Using the mmFATP1 cDNA as hybridization probe, a 1.6 kb partial cDNA clone was isolated from a human heart cDNA library. With 5' and 3' RACE procedures, the complete cDNA was isolated. Sequence comparisons with its mouse homologues identified this clone as hsFATP4.  相似文献   

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The lpA1/Gpcr26 locus encodes the first cloned and identified G-protein-coupled receptor that specifically interacts with lysophosphatidic acid. A murine full-length cDNA of size consistent with that seen on Northern blots (3.7 kb) was determined using 3' rapid amplification of cDNA ends. Analysis of genomic clones revealed that the gene is divided into five exons, with one intron inserted in the coding region for transmembrane domain VI and one exon encoding the divergent 5' sequence in another published cDNA clone variant (orphan receptor mrec1.3). This structure differs from the intronless coding region for a homologous receptor, Edg1, but is identical to another more similar orphan receptor (lpA2) that has been deposited with GenBank. Using backcross analysis, both exons 1 and 4 mapped to a proximal region of murine Chromosome 4 indistinguishable from the vacillans gene. Exon 4 also mapped to a second locus on proximal Chromosome 6 in Mus spretus, and this partial duplication was confirmed by Southern blot. The genomic structure indicates a distinct, divergent evolutionary lineage for the vzg-1/lpA1 subfamily of receptors compared to those of homologous orphan receptor genes.  相似文献   

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Genomic clones for a chitinolytic enzyme were isolated from a library of Sau 3A digested DNA from the tobacco hornworm, Manduca sexta, using a previously isolated chitinase cDNA clone as a probe [Kramer et al., Insect Biochem. Molec. Biol. 23, 691-701 (1993)]. Restriction enzyme mapping and Southern blot analysis of four genomic clones suggested that these are overlapping clones. Sequence analysis of the genomic clones and Southern blot analysis of total genomic DNA also suggest that the M. sexta genome has only one chitinase gene detectable by the cDNA probe. This gene is organized into at least 11 exons in a region spanning > 11 kb. The sequenced M. sexta chitinase gene has a series of exons corresponding to identifiable structural/functional regions of the protein. Similarities in structure and organization between the M. sexta chitinase gene and chitinase genes from other sources are described.  相似文献   

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The human CDX1 gene has been isolated from a small intestine cDNA library using a murine Cdx1 cDNA probe. The nucleotide sequence of CDX1 is 81% identical to murine Cdx1 and predicts a 265-amino-acid protein with 85% identity to the mouse protein (98% identity, including conservative amino acid changes). The CDX1 locus has been mapped to a cosmid contig from chromosome 5q31-q33, placing CDX1 approximately 100 kb distal to CSFIR. Expression of CDX1 in adults appears to be limited to the intestine and colon by Northern analysis, suggesting a possible role in the terminal differentiation of the intestine. Further analysis of CDX1 should elucidate the function of caudal-type homeobox genes in human development.  相似文献   

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A polyclonal antiserum raised against the purified glycosomal glycerol-3-phosphate dehydrogenase of Trypanosoma brucei brucei has been used to identify the corresponding cDNA clone in a T.b. brucei expression library. This cDNA was subsequently used to obtain genomic clones containing glycerol-3-phosphate dehydrogenase genes. Two tandemly arranged genes were detected in these clones. Characterization of one of the genes showed that it codes for a polypeptide of 353 amino acids, with a molecular mass of 37,651 Da and a calculated net charge of +8. Using the T.b. brucei gene as a probe, a corresponding glycerol-3-phosphate dehydrogenase gene was also identified in a genomic library of Leishmania mexicana mexicana. The L.m. mexicana gene codes for a polypeptide of 365 amino acids, with a molecular mass of 39,140 Da and a calculated net charge of +8. The amino-acid sequences of both polypeptides are 63% identical and carry a type-1 peroxisomal targeting signal (PTS1) SKM and -SKL at their respective C-termini. Moreover, the L.m. mexicana polypeptide also carries a short N-terminal extension reminiscent of a mitochondrial transit sequence. Subcellular localisation analysis showed that in L.m. mexicana the glycerol-3-phosphate dehydrogenase activity co-fractionated both with mitochondria and with glycosomes. This is not the case in T. brucei, where the enzyme is predominantly glycosomal. The two trypanosomatid sequences resemble their prokaryotic homologues (32-36%) more than their eukaryotic counterparts (25-31%) and carry typical prokaryotic signatures. The possible reason for this prokaryotic nature of a trypanosomatid glycerol-3-phosphate dehydrogenase is discussed.  相似文献   

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PURPOSE: Patients with active pars planitis have increased levels of a 36 kDa protein (p-36) in their circulation. The current studies were undertaken to determine the primary structure of this protein. METHODS: A degenerate oligonucleotide probe based on the amino terminal sequence of p-36 was used to identify a clone from a human spleen cDNA library. The cDNA insert was subcloned into the EcoR1 site of pUC-19, and both strands were sequenced. Southern blot analysis was used to study the genomic hybridization pattern. p-36 cDNA was subcloned in a pSG5 expression vector, and the construct was used to transfect COS-7 cells. RESULTS: The cDNA sequence contained an open reading frame of 966 base pairs encoding a protein of 322 amino acids, an untranslated region of 322 base pairs, and 2693 base pairs at the 5' and 3' ends, respectively. The deduced amino acid sequence showed 96.8% identity with the carboxy-terminal region of a yeast nucleopore complex protein, nup 100. Southern blot analysis of human genomic DNA revealed a simple hybridization pattern. Transfection of p-36 cDNA in COS-7 cells resulted in the presence of p-36 mRNA and expression of protein. CONCLUSIONS: The 36 kDa protein (p-36) detected at increased levels in the blood of patients with active pars planitis was cloned from a human spleen cDNA library. Its deduced amino acid sequence is homologous with the carboxy-terminal region of a nucleopore complex protein. Thus, we refer to this protein as nup36.  相似文献   

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