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L C Wu

Publications and source records attributed to L C Wu.

86 records · Page 5Linked to original sources
PubMed1987

Cell-specific expression of the human complement protein factor B gene: evidence for the role of two distinct 5'-flanking elements.

The human complement protein Factor B is encoded by a single gene in the major histocompatibility complex and is closely linked to the gene encoding the second component of complement C2. DNA sequencing, S1 mapping, and primer extension experiments have established that the transcription initiation site of the Factor B gene lies only 421 bp from the poly(A) site of the C2 gene. Deletion analysis of the Factor B 5'-flanking region has suggested the presence of cis-acting DNA elements that are essential for the cell-specific expression of the Factor B gene. These sequences extend into the 3' region of the C2 gene. We have defined an enhancer element in the 5'-flanking region in addition to the promoter element. Our results suggest that the cell-specific expression of the Factor B gene is dependent upon the combinatorial effect of both the promoter and the enhancer elements.

Base Sequence↗
PubMed1987

A yeast plasmid partitioning protein is a karyoskeletal component.

The Saccharomyces yeast plasmid, 2-micron circle, encodes a partitioning system that ensures equidistribution of plasmid molecules to both progeny following cell division. This system consists of two proteins encoded in plasmid genes REP1 and REP2 and a cis-active noncoding locus, designated REP3. We have raised antibodies against a REP1 beta-galactosidase fusion protein and used them to identify the authentic REP1 protein in plasmid-bearing yeast cells. We find that REP1 protein is located exclusively in the nucleus and co-purifies with a karyoskeletal protein subfraction operationally and morphologically equivalent to the nuclear matrix-pore complex-lamina fraction of higher cells. The carboxyl half of the REP1 protein exhibits strong sequence homology to myosin heavy chain, vimentin, and nuclear lamins A and C, indicating a fibrous structure for the protein. From these observations, we suggest that REP1 protein may promote plasmid partitioning by intercalating into the nuclear lamina of the host cell to provide dispersed anchorage sites for attachment of plasmid molecules.

Amino Acid Sequence↗
PubMed1986

Survival strategies of the yeast plasmid two-micron circle.

The multicopy yeast plasmid 2-micron circle uses a number of strategies to insure its persistence in its host. The plasmid confers no selective phenotype to the cell in which it is resident. Nonetheless, the plasmid is lost at less than 1 per 10(5) cell divisions during continuous exponential growth. We have determined that the plasmid persists at least in part due to the ability of the plasmid to amplify its mean copy number when its cellular copy level is low and to distribute plasmid molecules equally between mother and daughter cells at mitosis. We have found that amplification of plasmid copy number occurs by a novel mechanism in which site-specific recombination induces a transient shift in the mode of replication from theta to rolling circle. Equitable partitioning of plasmid molecules requires plasmid-encoded proteins and a centromere-like segment on the plasmid. We have accumulated evidence consistent with a model of partitioning in which the partitioning proteins form a transnuclear structure that is responsible for distributing plasmid molecules throughout the nucleus prior to cell division. In this chapter we describe evidence supporting the existence and mode of action of these two plasmid strategies and discuss the extent to which these strategies may be a pervasive facet of the biology of eukaryotic extrachromosomal elements.

Amino Acid Sequence↗
PubMed1985

Technetium-99m HIDA hepatic lobar distribution and retention ratios in detection of intrahepatic lithiasis.

Technetium-99m HIDA hepatic lobar distribution and retention ratios were developed to evaluate patients with intrahepatic lithiasis. The data of 57 cases were analyzed. Results reveal a highly significant difference in these ratios between the patients and normal individuals. They are simple, objective, and easily obtainable. Thus, the determination of these ratios may replace [99mTc]HIDA sequential scintiphotography, which is qualitative and time consuming, for screening intrahepatic lithiasis.

Calculi↗
PubMed1983

FORTRAN algorithms for evaluating Fourier transforms of line spread functions.

FORTRAN IV algorithms are presented for calculating the modulation transfer function, the phase transfer function, the modulation transfer function area, an information transfer function, and the optimum frequency response as well as plotting the curves for these matrices. An important feature of the programs is an editing routine.

Computers↗
PubMedDate not supplied

Random amplified polymorphic DNA analysis of culture collection strains of Candida species.

Random amplified polymorphic DNA (RAPD) profiles, obtained when screening culture collection strains of Candida spp., showed several species to be highly heterogeneous. The RAPD-defined groups were as follows: C. catenulata, two groups among five strains; Debaryomyces hansenii (anamorph C. famata), three groups among five strains; C. sake, three groups among three strains; C. intermedia, two groups among two strains; C. rugosa, two groups among three strains and C. parapsilosis, three groups among four strains. The five strains of Issatchenkia orientalis (anamorph C. krusei) belonged to a single RAPD-defined group. The two strains of the teleomorphic yeast Arxiozyma telluris had distinct RAPD profiles but neither resembled profiles of its anamorph, C. pintolopesii. The two varieties of C. pintolopesii had different RAPD profiles. Researchers are cautioned that organisms with the same name may not be closely related.

Animals↗
PubMedDate not supplied

Neonatal coxsackievirus B1 infection associated with severe hepatitis: report of three cases.

Coxsackievirus B infection may cause fulminant disease in the neonate. In most reports the prominent symptoms have been recognized as myocarditis and meningoencephalitis, and a majority were caused by type B2 to B5. Coxsackie B1 was a rare cause. From December 1993 to April 1994 three newborns were admitted to this Hospital with similar presentations of acute hepatitis and thrombocytopenia. Coxsackie B1 virus was isolated from all at one or two sites including rectal swab, throat swab and urine. One fatal case had had symptoms from birth; the disease progressed rapidly initially with a strikingly high liver enzyme; respiratory failure was noted; acute renal failure then happened later and the baby expired in two weeks. The other two patients survived, though one also had severe fulminant hepatitis. In that case onset of the disease was late at 28 days old. The other's clinical course was mild from the beginning. Myocarditis or central nervous system involvement were apparently not the significant presentations. Because the three babies all came from areas near this city (Chung-Ho and Pan-Chiao), attention should be drawn to the prevalence of coxsackie B1 virus infection in the total community.

Acute Disease↗