Biomaterial Database

Rift Valley fever virus M segment: phlebovirus expression strategy and protein glycosylation. 1989

L T Kakach, and J A Suzich, and M S Collett

Molecular Genetics, Inc., Minnetonka, Minnesota 55343.

The M segment RNA of Rift Valley fever virus (RVFV) encodes four gene products: the two viral envelop glycoproteins G2 and G1, a glycosylated 78-kDa protein, and a nonglycosylated 14-kDa protein. These proteins are generated from a single open reading frame (ORF) by a strategy involving independent translational initiations at both the first and second in-phase ATG codons and co-translational processing of primary polyprotein products. The ORF encodes six sites for N-linked glycosylation: one present in the "preglycoprotein region" preceding the coding sequences of the mature envelop glycoproteins, and within the coding sequences of both the 78- and 14-kDa proteins; one site in the glycoprotein G2 coding region, also present in the 78-kDa protein; and four sites within glycoprotein G1. From analyses of RVFV proteins produced in cells infected with recombinant vaccinia viruses expressing various M segment regions, we show glycoprotein G2 was glycosylated at its single site and glycoprotein G1 at at least three sites. Both sites for N-linked glycosylation in the 78-kDa protein were occupied with glycan. This latter result indicated the preglycoprotein region glycosylation site was utilized in the 78-kDa protein, but this same site within the 14-kDa protein was not. Further analysis showed utilization of this glycosylation site, as well as proteolytic processing at the amino terminus of the mature glycoprotein G2, appeared to be determined by initiation codon usage. The two-site translational initiation expression strategy of this phlebovirus M segment and its role in the control of post-translational protein modification and processing are discussed.

UI	MeSH Term	Description	Entries
D011233	Precipitin Tests	Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.	Precipitin Test,Test, Precipitin,Tests, Precipitin
D002043	Bunyaviridae	A family of viruses, mainly arboviruses, consisting of a single strand of RNA. Virions are enveloped particles 90-120 nm diameter. The complete family contains over 300 members arranged in five genera: ORTHOBUNYAVIRUS; HANTAVIRUS; NAIROVIRUS; PHLEBOVIRUS; and TOSPOVIRUS.
D005786	Gene Expression Regulation	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.	Gene Action Regulation,Regulation of Gene Expression,Expression Regulation, Gene,Regulation, Gene Action,Regulation, Gene Expression
D006023	Glycoproteins	Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins.	C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated
D006031	Glycosylation	The synthetic chemistry reaction or enzymatic reaction of adding carbohydrate or glycosyl groups. GLYCOSYLTRANSFERASES carry out the enzymatic glycosylation reactions. The spontaneous, non-enzymatic attachment of reducing sugars to free amino groups in proteins, lipids, or nucleic acids is called GLYCATION (see MAILLARD REACTION).	Protein Glycosylation,Glycosylation, Protein
D012296	Rift Valley fever virus	A mosquito-borne species of the PHLEBOVIRUS genus found in eastern, central, and southern Africa, producing massive hepatitis, abortion, and death in sheep, goats, cattle, and other animals. It also has caused disease in humans.
D014764	Viral Proteins	Proteins found in any species of virus.	Gene Products, Viral,Viral Gene Products,Viral Gene Proteins,Viral Protein,Protein, Viral,Proteins, Viral