Analysis of polypeptides synthesized in bovine respiratory syncytial virus-infected cells

Abstract

Ten virus-specific polypeptides ranging in molecular weight from approximately 200k to 11k were identified in bovine respiratory syncytial virus (BRSV-)infected cells. Time course analysis of the induction of the viral polypeptides indicated that they could be detected as early as 30 min post-infection and their synthesis reached a plateau 12 h after infection. Cell free translation of total infected-cell mRNA in a rabbit reticulocyte system yielded 7 proteins corresponding in size to virus-specific proteins synthesized in BRSV-infected cells. The P protein was highly phosphorylated; G and F were identified as glycoproteins by [3H]glucosamine labeling. Glycosylation of G protein was largely resistant to tunicamycin, suggesting that the majority of the carbohydrate residues are attached via O-glycosidic bonds, whereas the F protein was N-linked glycosylated. Tunicamycin caused a drastic reduction in the yield of infectious virus titer indicating that the carbohydrate moieties serve a critical role in the infectious cycle of BRSV.

Sequence comparison between the phosphoprotein mRNAs of human and bovine respiratory syncytial viruses identifies a divergent domain in the predicted protein

“…The predicted protein is 241 amino acids long, identical in length to the P proteins of HRSV. It has a calculated Mr of 27 208, whereas that calculated previously from SDS-polyacrylamide gels is 34K (Mallipeddi et al, 1990). Similar discrepancies have also been found between the calculated Mr and that deduced from the mobility of HRSV P proteins in gels (Johnson & Collins, 1990).…”

“…Although BRSV and HRSV are antigenically related, they differ in their pattern of reactivity with monoclonal antibodies (Mufson et al, 1985;()rvell et al, 1987;Beeler & van Wyke Coelingh, 1989). It has been shown that like that of HRSV, the genome of BRSV encodes 10 mRNAs (Lerch et al, 1989), and that the protein composition of these viruses is very similar, with only minor differences in Mr between corresponding proteins (Cash et al, 1977;Lerch et al, 1989;Trudel et al, 1989;Mallipeddi et al, 1990). To delineate the genetic basis for the differences between HRSV and BRSV, we and others have undertaken cDNA cloning and nucleotide sequencing of BRSV genes for comparison with the sequences of the genes of HRSV.…”

Bovine respiratory syncytial virus: first serological evidence in Uruguay

“…For these reasons, recombinant BRSV proteins are more suitable for use as antigens in diagnostic ELISA. The N protein of BRSV appears to be an ideal candidate for use as an antigen in diagnostic ELISA, since it is the most abundant viral protein in BRSV-infected cells [12,13] and antibodies to the N protein appear early and predominate during BRSV infection [25].…”

“…Wild-type baculovirus, and recombinant baculoviruses were plaquepurified and propagated as described by Summers and Smith (1987) [21]. The construction and characterization of the recombinant baculovirus encoding the BRSV N protein were accomplished by established methods as described before [13,17].…”

“…The nucleocapsid (N) protein, which has been identified as a polypeptide of M r 42 kDa, is the most abundant protein in BRSV-infected cells [12,13]. The N protein is also highly conserved (> 99%) between two BRSV strains [1].…”