ABSTRACT
The penton capsomer of mammalian adenoviruses consists of a trimeric, long and thin fibre inserted into a pentameric base. The avian adenoviruses possess a penton which presents another symmetry mismatch: each pentameric base is associated with two fibres. Here we have studied the morphology of the penton of CELO virus, an avian adenovirus, and we have determined the sequence of both fibres, one long and one short. The short fibre is probably associated with the base in the same way as the mammalian viral fibres and we will discuss how the long fibre could be attached. The shafts of all known adenovirus fibres consist of a series of 15-residue repeats. The avian virus fibres show a more complicated and less regular shaft repeat structure with single, double and triple repeats. The sequences of the receptor binding (head) domains of both fibres are very different from all other known fibre head domains and very different from each other, suggesting that the two fibres might bind to different receptors. The genome organization of the sequenced region is rather different from that in human adenoviruses. In particular, a region homologous to the human virus E3 region was not found at the position where it normally occurs in the human virus genome.
Subject(s)
Aviadenovirus/chemistry , Capsid Proteins , Capsid/chemistry , Viral Structural Proteins/genetics , Amino Acid Sequence , Aviadenovirus/ultrastructure , Binding Sites , Capsid/ultrastructure , Genes, Viral/genetics , Humans , Molecular Sequence Data , Open Reading Frames/genetics , Repetitive Sequences, Nucleic Acid/genetics , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Viral Structural Proteins/ultrastructureABSTRACT
The Escherichia coli genes dicF and dicB encode division inhibitors, which prevent the synthesis and activity, respectively, of the essential division protein FtsZ. A mutation at the C-terminal end of the RNA polymerase beta subunit renders cells resistant to both inhibitors. In the mutant strain the level of the ftsZ gene product is higher than in the wild type. Disruption of rpoS, which encodes the stationary phase sigma factor sigma S, lowers FtsZ protein levels in the mutant, and partially restores sensitivity to the inhibitors.
Subject(s)
Bacterial Proteins/genetics , Cell Division/genetics , Cytoskeletal Proteins , Escherichia coli/genetics , Sigma Factor/genetics , Amino Acid Sequence , Bacterial Proteins/biosynthesis , Base Sequence , Chromosome Mapping , DNA-Directed RNA Polymerases/genetics , Escherichia coli/cytology , Gene Expression Regulation, Bacterial/genetics , Genes, Bacterial , Immunoelectrophoresis , Isopropyl Thiogalactoside/pharmacology , Molecular Sequence Data , Mutation , Phenotype , Suppression, Genetic , Transcription, GeneticABSTRACT
The gene encoding the penton base of human adenovirus (Ad) type 3 has been sequenced. The resulting amino-acid sequence has an Arg-Gly-Asp (RGD) motif located near its middle in a hydrophilic region. The same motif is found in serotypes 2, 5 and 12. This sequence was found [Wickham et al., Cell 73 (1993) 309-319] to be involved in the internalisation of Ad2 through an interaction with some specific integrins.
