TY - JOUR
T1 - Profilin is required for optimal actin-dependent transcription of respiratory syncytial virus genome RNA
AU - Burke, Emily
AU - Mahoney, Nicole M.
AU - Almo, Steven C.
AU - Barik, Sailen
PY - 2000
Y1 - 2000
N2 - Transcription of human respiratory syncytial virus (RSV) genome RNA exhibited an obligatory need for the host cytoskeletal protein actin. Optimal transcription, however, required the participation of another cellular protein that was characterized as profilin by a number of criteria. The amino acid sequence of the protein, purified on the basis of its transcription- optimizing activity in vitro, exactly matched that of profilin. RSV transcription was inhibited 60 to 80% by antiprofilin antibody or poly-L- proline, molecules that specifically bind profilin. Native profilin, purified from extracts of lung epithelial cells by affinity binding to a poly-L- proline matrix, stimulated the actin-saturated RSV transcription by 2.5- to 3-fold. Recombinant profilin, expressed in bacteria, stimulated viral transcription as effectively as the native protein and was also inhibited by poly-L-proline. Profilin alone, in the absence of actin, did not activate viral transcription. It is estimated that at optimal levels of transcription, every molecule of viral genomic RNA associates with approximately the following number of protein molecules: 30 molecules of L, 120 molecules of phosphoprotein P, and 60 molecules each of actin and profilin. Together, these results demonstrated for the first time a cardinal role for profilin, an actin-modulatory protein, in the transcription of a paramyxovirus RNA genome.
AB - Transcription of human respiratory syncytial virus (RSV) genome RNA exhibited an obligatory need for the host cytoskeletal protein actin. Optimal transcription, however, required the participation of another cellular protein that was characterized as profilin by a number of criteria. The amino acid sequence of the protein, purified on the basis of its transcription- optimizing activity in vitro, exactly matched that of profilin. RSV transcription was inhibited 60 to 80% by antiprofilin antibody or poly-L- proline, molecules that specifically bind profilin. Native profilin, purified from extracts of lung epithelial cells by affinity binding to a poly-L- proline matrix, stimulated the actin-saturated RSV transcription by 2.5- to 3-fold. Recombinant profilin, expressed in bacteria, stimulated viral transcription as effectively as the native protein and was also inhibited by poly-L-proline. Profilin alone, in the absence of actin, did not activate viral transcription. It is estimated that at optimal levels of transcription, every molecule of viral genomic RNA associates with approximately the following number of protein molecules: 30 molecules of L, 120 molecules of phosphoprotein P, and 60 molecules each of actin and profilin. Together, these results demonstrated for the first time a cardinal role for profilin, an actin-modulatory protein, in the transcription of a paramyxovirus RNA genome.
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U2 - 10.1128/JVI.74.2.669-675.2000
DO - 10.1128/JVI.74.2.669-675.2000
M3 - Article
C2 - 10623728
AN - SCOPUS:0033989377
SN - 0022-538X
VL - 74
SP - 669
EP - 675
JO - Journal of virology
JF - Journal of virology
IS - 2
ER -