The Nucleotide Sequence of RNA1 of Lettuce big-vein virus, Genus Varicosavirus, Reveals Its Relation to Nonsegmented Negative-Strand RNA Viruses

AbstractThe complete nucleotide sequence of RNA1 from Lettuce big-vein virus (LBVV), the type member of the genus Varicosavirus, was determined. LBVV RNA1 consists of 6797 nucleotides and contains one large ORF that encodes a large (L) protein of 2040 amino acids with a predicted Mr of 232,092. Northern blot hybridization analysis indicated that the LBVV RNA1 is a negative-sense RNA. Database searches showed that the amino acid sequence of L protein is homologous to those of L polymerases of nonsegmented negative-strand RNA viruses. A cluster dendrogram derived from alignments of the LBVV L protein and the L polymerases indicated that the L protein is most closely related to the L polymerases of plant rhabdoviruses. Transcription termination/polyadenylation signal-like poly(U) tracts that resemble those in rhabdovirus and paramyxovirus RNAs were present upstream and downstream of the coding region. Although LBVV is related to rhabdoviruses, a key distinguishing feature is that the genome of LBVV is segmented. The results reemphasize the need to reconsider the taxonomic position of varicosaviruses

Neurotrophic properties of leptomeninges

The leptomeninges, consisted of pia mater and arachnoid, cover the surface of brain parenchyma. Leptomeningeal cells produce a number of biologically active proteins, including prostaglandin-D synthase, cyclooxygenase-1, -2, insulin-like growth factor-II, insulin-like growth factor-binding proten-2, and apolipoprotein E, released into the cerebrospinal fluid. The involvement of leptomeninges in neurotrophic, scavenging, and transport activities as well as inflammatory responses, associated with the brain, is reviewed.Biomedical Reviews 1999; 10: 31-36