Morphology and Antigenic Properties of Recombinant Analogs of the Marburg Virus Nucleoprotein

The full-length gene for Marburg virus (MV) nucleoprotein (NP) was cloned in prokaryotic pQE32 under the control of the T5 promoter and in eukaryotic pTM1 under the control of the T7 RNA polymerase promoter. Recombinant NP was synthesized in Escherichia coliand in human kidney cell line 293 cotransfected with recombinant vaccinia virus vTF7-3 expressing T7 RNA polymerase. On evidence of electron microscopy with immune detection, recombinant NP formed tubules of two types in E. coliand of a single type in cell line 293. ELISA and immunoblotting with polyclonal and monoclonal antibodies revealed common antigenic determinants in recombinant NP and natural MV NP.     

Identification of developmentally regulated expression of MuSK in astrocytes of the rodent retina

One of the master regulators of postsynaptic neuromuscular synaptogenesis is the muscle-specific receptor tyrosine kinase (MuSK). In mammals prominent MuSK expression is believed to be restricted to skeletal muscle. Upon activation by nerve-derived agrin MuSK-dependent signalling participates in both the induction of genes encoding postsynaptic components and aggregation of nicotinic acetylcholine receptors (AChR) in the subsynaptic muscle membrane. Strikingly, expression of certain isoforms of nerve-derived agrin can also be detected in the CNS. In this study, we examined the expression of MuSK in the brain and eye of rodents. In the retina MuSK was expressed in astrocytes between postnatal days 7 and 14, i.e. at the time when the eyes open. We found that agrin was localized adjacent to MuSK-expressing astrocytes which in turn were detected close to the inner limiting membrane of the rodent retina. In summary, the presence of MuSK on retinal astrocytes suggests a novel role of MuSK signalling pathways in the CNS.     

Submicroscopic characteristics of Marburg virus and its mini genome analog replication in cell cultures

Marburg virus (Filoviridae) causes severe hemorrhagic fevers in humans and some lower primates with high mortality. The virus genome is formed by a single strand RNA of negative polarity, coding for seven structural proteins. We studied the ultrastructure of Marburg virus replicative cycle and replication of its minigenome RNA (coding for the terminal areas of the genome) in the presence of helper virus in VERO fibroblastoid cell culture and epithelioid MDCK cell culture. Ultrastructural parameters of Marburg virus multiplication in these cell cultures are virtually the same. The virus nucleocapsid assembly is performed on the outer side of EPR membrane and is not associated with preliminary accumulation of the precursor material. Virions form by budding on plasmalemma and are located on the entire surface in Vero cells and only on the basolateral surface of MDCK cells. Replication of minigenome analog of marburg virus is associated with impairment of the helper virus morphogenesis and formation of spherical pseudoviral particles.     

Comparative study of the morphology and antigenic properties of recombinant analogs of a Marburg virus nucleoprotein]

The full-length gene for Marburg virus (MV) nucleoprotein (NP) was cloned in prokaryotic pQE32 under the control of the T5 promoter and in eukaryotic pTM1 under the control of the promoter for T7 RNA polymerase. Recombinant NP was synthesized in Escherichia coli and in human kidney cell line 293 cotransfected with recombinant vaccinia virus vTF7-3 expressing T7 RNA polymerase. On evidence of electron microscopy with immune detection, recombinant NP formed tubules of two types in E. coli and of a single type in cell line 293. ELISA and immunoblotting with polyclonal and monoclonal antibodies revealed common antigenic determinants in recombinant NP and natural MV NP.