Relationships between the RNA Components of Chronic Bee-Paralysis Virus and those of Chronic Bee-Paralysis Virus Associate

Abstract

SUMMARYThe RNA components of chronic bee-paralysis virus (CPV) and those of chronic bee-paralysis virus associate (CPVA) have been compared. CPV has five singlcstranded RNA components, two larger RNAs dcsignatcd l (tool. wt. 1.35 × 106; 4200 nucleotidcs) and 2 (mol. wt. 0.9 × 106; 2800 nuclcotides), and three smaUcr RNAs designated 3a, 3b and 3c, each with mol. wt. 0-35 × I06 (I I00 nuclcotidcs). CPVA has three single-stranded RNA components dcsignatcd A, B and C, each with tool. wt. 0.35 × 106 (I 100 nuclcotides). Gcl clcctrophorctic and T~ fingerprint analyses have shown that RNAs 3a, 3b and 3c are very similar to, and probably identical to, RNAs A, B and C respectively, i.e. thcse thrcc RNAs appear to bc cncapsidated in both CPV and CPVA particles. A positive correlation was observed between the proportion of RNAs 3a, 3b and 3c in CPV particles and the amount of CPVA (and hence RNAs A, B and C) which had replicated. Fingerprint analysis has shown that RNAs A, B and C arc distinct but related and also that about 50 ~ of the sequence of each thcse three RNAs is homologous with RNA 2. It is therefore possible that, although CPV and CPVA are scrologically unrelated, the RNAs of CPVA have evolved from CPV RNA 2. INTRODUCTIONChronic bee-paralysis virus (CPV), which causes a trembling condition soon followed by death in the adult honey bee, Apis mellifera (Bailey et al., 1963), consists of ellipsoidal particles falling into four size classes with modal lengths of 30, 40, 55 and 65 nm, each approximately 20 nm wide. These components have sedimentation coefficients of 82S, 97S to 106S, 110S to 124S and 125S to 136S respectively and are found in the same relative proportions in preparations from naturally infected bees, from artificially infected bees and from bees injected with terminal dilutions of bottom component only. In caesium chloride gradients, all size classes have a buoyant density of 1.33 g/ml. The particles contain single-stranded RNA with a base composition of 20~ G, 24~ o A, 28 ~ C and 28 ~o U. Serologically, the components are indistinguishable (Bailey, 1976;Bailey et al., 1968).Chronic bee-paralysis virus associate (CPVA) is frequently found in bees infected with CPV (Bailey, 1976). It consists of 17 nm isometric particles which are serologicaUy unrelated to those of CPV. The virus particles have a buoyant density of 1.38 g/ml in caesium chloride, a sedimentation coefficient of 41S, and contain single-stranded RNA. CPVA cannot multiply when injected into bees unless CPV is included in the inoculum, which suggests that CPVA and CPV are related as satellite and helper viruses (Bailey et al., 1980)~ However, CPVA sometimes multiplies in bees injected with CPV preparations which contain no detectable CPVA. In this paper, we report the identification of several RNA components from CPV and CPVA and the results of comparison of these RNAs by T~ oligonucleotide fingerprinting.

Relationships between the Multiplication of Chronic Bee-Paralysis Virus and its Associate Particle

“…The results in Fig. 3 also confirm the observations of Overton et al (1982) that the proportion of CPVA RNA (RNAs 3a, b and c) encapsidated in CPV particles increases relative to RNAs 1 and 2 as CPVA replication increases. Fig.…”

“…In contrast when larger amounts of RNAs 1 and 2, together with smaller amounts of RNA 3, are formed, the RNAs may be packaged together to produce long particles and also separately to produce short particles. In such a situation the overall ratios of the RNA species in long and short particles could be similar, as found for one CPV preparation by Overton et al (1982). Virions containing all the genome segments would be expected to be more infective than those in which the genome segments are encapsidated separately, particularly at low multiplicities of infection.…”

“…Polyacrylamide gel electrophoresis (PAGE) of RNA, followed by staining and scanning of gels, were carried out as previously described (Overton et al, 1982).…”

“…wt. respectively) (Overton et al, 1982). The properties of CPVA and CPV and their RNA components are summarized in Table 1.…”

Detection of chronic honey bee (Apis melliferaL.) paralysis virus infection: application to a field survey

“…ml -1 [4]. The virus particles have one capsid protein of 23.5 kDa [4] and contain five single-stranded RNAs [20].…”