Effect of vaccinia on VSV protein synthesis in untreated and interferon-treated cells

APPEAR

SYNTHESIS TO REQUIRE

OF LA CROSSE VIRUS FULL-LENGTH ON-GOING PROTEIN SYNTHESIS

mRNAs

DOES

44

CHRISTINE BELLOCQ, RAMASWAMY PAJU, JEAN PATTERSON and DANIEL KOLAKOFSKY, Dept of Microbiology, University of Geneva, 9, av. de Champel, 1211 Geneve 4, Switzerland Other workers (Abraham and Pattnaik) have previously reported that inhibitors of protein synthesis block all bunyavirus RNA synthesis, including mRNAs. We have confirmed these findings with La Crosse virus in vivo and extended these studies to transcription -in vitro. Usingpurified La Crosse virions, S genome transcripts were shown to represent discrete species but of relatively short length. When the transcription reaction was carried out in the presence of a reticulocyte lysate competent to carry out protein synthesis, full-length S mRNA was produced and the shorter transcripts were no longer made. Addition of cycloheximide at low concentrations to the coupled transcription translation system in vitro abolished the synthesis of full-length S mRNA and led to -the appearance of 'some of the shorter transcripts. A discussion of this unusual phenomenon will be attempted.

45

EFFECT OF VACCINIA ON VSV PROTEIN SYNTHESIS IN UNTREATED AND INTERFERONTREATED CELLS PATRICIA WHITAKER-DOWLING, ROSEMARY JAGUS, and JULIUS S. YOUNGNER, Departments of Microbiology and Biochemistry, University School of Medicine, Pittsburgh, PA 15261, U.S.A. Coinfection almost

with vaccinia

lO-fold.

inhibitory

effects

of VSV yield.

cantly

increase

Although

is dramatically

treatment

is known

treatment,

coinfection

stimulated

in mouse L cells by

resulting

in a 100 to 1000-fold

with vaccinia

by double

to induce a protein

RNA, phosphorylates

and thereby blocks

protein

in an inhibition

dsRNA-dependent

VSV growth

is able to rescue VSV from the

the amount of VSV mRNA found in infected

synthesis

results

increases

vaccinia

of interferon

rescue

double-stranded

virus

In addition,

kinase

addition,

immunoblots

dependent

modification

infection.

kinase which,

eukaryotic

synthesis.

does not significells, VSV protein Interferon

in the presence

initiation

It is important

is found in high constitutive focusing

of eIF-2. 23

of

factor 2 (eIF-2)

We find that vaccinia

of this kinase.

of isoelectric

of Pittsburgh,

infection

to note that the

levels in L cells.

gels reveal a vaccinia-

In