Supercoiled DNA of nuclear polyhedrosis virus ofGalleria mellonella L.

Abstract

Supercoiled infectious DNA was isolated from nuclear polyhedrosis virus infecting great wax moth Galleria mellonella L.) Covalently closed DNA molecules constitute approximately 10--30 per cent in our preparations. These molecules dissappear during storage. Electron micrographs of supercoiled and open circular molecules are presented. Length of the open rings is about 50--52 micron. Infectivity of different DNA forms is discussed.

Macromolecular structure of nuclear polyhedrosis virus genome

“…Infectivity of large supercoiled NPV DNA molecules with a molecular weight of about 100 × 10¢ has been demonstrated (17). However, this finding does not resolve the problem about the size and structural characteristics of the NPV genome, since infective DNA preparations containing both open circular molecules (also with a molecular weight of about 100 × 106) and linear moleeules of different length have been found.…”

“…The M-I strain of GmL NPV was used (17). The insect larvae used and their method of infection with NPV have been described previously (17).…”

“…aH-DNA Puri/ication From GmL NP V DNA was extracted with phenol-detergent or detergent-salt (6) as previously described (17). Crystalline CsC1 (final concentration 1.t g/ml) was added to supernatants for protein flotation when DNA was extracted with detergent-salt.…”

Baculovirus Replication

“…This is probably a consequence of the interaction with an extremely basic protein found in the nucleocapsid (Tweeten et al, 1980 a;Bud & Kelly, 1980 a) and which is uniformly distributed throughout the nucleocapsid (Burley et al, 1982) It is the only DNA-binding protein contained by the virus . It is also worth mentioning that the DNA is infectious for cells in culture and insect larvae (Skuratovskaya et al, 1977) provided it is circular although not necessarily covalently closed (Kelly & Wang, 1981).…”

“…Not all the DNA contained by baculoviruses is ccDNA and generally no more than 30% is recovered as ccDNA although most of the DNA is nicked circular (nc)DNA (Summers & Anderson, 1972;Skuratovskaya et aL, 1977). The two forms of the DNA are equally infectious, although linear derivatives are not (Kelly & Wang, 1981).…”