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U Krempien

Publications and source records attributed to U Krempien.

5 recordsLinked to original sources
PubMed1987

Reduced steady-state levels of vaccinia virus-specific early mRNAs in interferon-treated chick embryo fibroblasts.

The molecular mechanism of interferon action on vaccinia virus-specific immediate early protein synthesis was studied in interferon-treated chick cells. In line with previous observations, the synthesis of total vaccinia WR virus-specific mRNA, thymidine kinase (TK) mRNA, and several other early mRNAs was detectable by short [3H]uridine pulses. Under conditions of over 90% inhibition of poxvirus-specific TK induction, accumulation of TK mRNA was strongly inhibited. Northern blot analysis revealed strong degradation of residual TK mRNA prepared from interferon-treated chick embryo fibroblasts (CEF). Blot hybridization analysis using total vaccinia DNA and restriction fragment N as probes demonstrated a generally reduced steady-state amount of vaccinia virus-specific early mRNAs in interferon-treated CEF. When CEF were infected with a recombinant vaccinia virus strain into the TK gene of which the chloramphenicol acetyltransferase gene had been inserted, CAT activity was far lower in interferon-treated than in untreated CEF. We conclude that signals that specify rapid breakdown of viral TK mRNA in interferon-treated CEF are located in the regions flanking the coding sequences of the viral TK gene.

Acetyltransferases↗
PubMed1985

Purification of chick interferon by zinc chelate affinity chromatography and sodium dodecylsulfate-polyacrylamide gel electrophoresis.

An improved purification method for chick interferon from the allantoic fluid of embryonated chick eggs is described. Interferon prepurified by perchloric acid treatment, zinc acetate precipitation, and chromatography on SP-Sephadex C-25 was further enriched by column chromatography on zinc chelate. Analysis on sodium dodecylsulfate polyacrylamide gel electrophoresis of the interferon preparation with a specific activity of 8 X 10(5) units/mg protein shows that the major antiviral activity migrated in a broad band in the range of 20-29 kD molecular weight. Several protein bands were stainable with Coomassie blue and silver nitrate in this molecular weight range. Between 80 and 95% of the total protein charged to the gel could be removed from the interferon containing fractions by sodium dodecylsulfate polyacrylamide gel electrophoresis.

Allantois↗
PubMed1984

Synthesis of early vaccinia-virus-specific enzymes under conditions of immediate early gene expression.

Cycloheximide reversal experiments in chick embryo fibroblasts and mouse L-929 cells indicate that the poxvirus-induced enzymes DNA polymerase and 'alkaline' DNase are immediate early gene products of the virus. In contrast to the vaccinia-WR-coded enzyme under conditions of immediate early gene expression the cowpox-virus-induced DNA polymerase is made only in very small amounts. The studies are consistent with the notion that all poxvirus-specific early proteins may be immediate early viral gene products.

Animals↗
PubMed1984

Herpes simplex virus-induced cell surface protrusions.

Cell surface alterations following herpes simplex virus infection were studied by scanning electron microscopy at different times after infection of chick embryo fibroblasts and Vero cells. Beginning at 4 h, an increasing number of cells showed numerous microvillus protrusions 0.12-0.18 micron in diameter and 0.3 micron in length. These structures could also be stained on Vero cells with fluorescent phalloidin, indicating the presence of filamentous actin within them. At 12 h, the number of chick embryo fibroblasts with virus-induced microvillus-like structures began to decrease. There was an increase in virus titer in the medium beginning at 24 h, and it was therefore considered unlikely that the microvilli induced earlier had any function in virus release. Similar to poxvirus-induced microvilli formation, DNA and protein synthesis inhibitors prevented the induction of microvilli, indicating the involvement of a late viral function. N1-isonicotinoyl-N2-3-methyl-4-chlorobenzoylhydrazine inhibited the formation of herpesvirus-induced microvilli in chick embryo fibroblasts but not in Vero cells. As this inhibitor had no effect on virus replication in either cell type, it is likely that the inhibition of microvillus formation was due to an anticellular activity of the drug.

Animals↗