The influenza a virus protein PB1 undergoes a conformational rearrangement during mRNA primed influenza virus mRNA synthesis

REARRANGEMENT

THE INFLUENZA A VIRUS PROTEIN PB UNDERGOES A CONFORMATIONAL DURING mRNA- PRIMED INFLUENZA VIRUS mRNA SYNTHESIS.

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STIG STRIDHl, ROELF DATEMA' and CHRISTOPH SCHOLTISSEK, 1 Antiviral Chemotherapy, Astra Lakemedel AB, S-151 85 Sodertalje,

Sweden. Phosphonoformic

acid could

in contrast

the initiation

of mRNA synthesis

phosphonoformic

acid inhibited

the elongation plaque

in mRNA primed

virus mutants,

undergoes

results

rearrangement

by exogenous

not inhibit

mRNA. However,

in ApG primed

reactions

and

in either PB1 or PA, it was and elongation

of mRNA primed

that the RNA polymerase

in mRNA primed reactions,

this

acid not until after the initi-

does not occur

COMPLEMENTATION CONSTITUTIVELY

phosphate

Using viral cores from fowl

indicate

to phosphonoformic

ation. This rearrangement

CELL LINES PROTEINS

reactions.

both initiation

These

a conformational

make PBT susceptible

when primed

the initiation

temperature-sensitive

shown that PB1 catalyzes virus mRNA synthesis.

to pyridoxal

in ApG primed

reactions.

OF INFLUENZA VIRUS TS MUTANTS USING EXPRESSING INFLUENZA VIRUS POLYMERASE

M. KRYSTAL, RUAN LI, D. LYLESl and P. PALESE, Mt Sinai School of Medicine of Cuny, New York, NY 10029 and 1Wake Forest University Medical Center, Winston-Salem, NC27103 Bovine papilloma virus vectors were used to construct Cl27 cell lines constitutively expressing either one or all three influenza polymerase proteins. These transformed cell lines were tested for their ability to complement the growth of temperature sensitive (ts) influenza virus mutants incubated at the nonpermissive temperature. Cell lines expressing either the PB2, PBl or PA proteins did not exhibit significant complementation levels with ts mutants from their respective complementation groups. However, cell lines expressing all three polymerase genes were able to complement the growth of PB2 and/or PA ts mutants at the nonpermissive temperature. Depending on the transformed cell line and the ts mutant used, viral yields at the nonpermissive temperature were up to lOOO-fold higher in the complementing cell line than in Cl27 cells. 17

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