title: Analysis of the ORF2 of human astroviruses reveals lineage diversification, recombination and rearrangement and provides the basis for a novel sub-classification system.
abstract: Canonical human astroviruses (HAstVs) are important enteric pathogens that can be classified genetically and antigenically into eight types. Sequence analysis of small diagnostic regions at either the 5' or 3' end of ORF2 (capsid precursor) is a good proxy for prediction of HAstV types and for distinction of intratypic genetic lineages (subtypes), although lineage diversification/classification has not been investigated systematically. Upon sequence and phylogenetic analysis of the full-length ORF2 of 86 HAstV strains selected from the databases, a detailed classification of HAstVs into lineages was established. Three main lineages could be defined in HAstV-1, four in HAstV-2, two in HAstV-3, three in HAstV-4, three in HAstV-5 and two in HAstV-6. Intratypic (inter-lineages) ORF2 recombinant strains were identified in type 1 (1b/1d) and type 2 (2c/2b) with distinct crossover points. Other potential intratypic recombinant strains were identified in type 3, type 5 and type 6. In addition, a type-1b strain with a large insertion (~600 bp) of heterologous RNA in the N-terminal region and a type-6 strain with a large RNA rearrangement in the hypervariable region were identified. The classification scheme was integrated in a novel nomenclature system suitable for designation of HAstV strains.
authors.affiliation: Dipartimento di Medicina Veterinaria, Università Aldo Moro di Bari, Valenzano, Italy, vito.martella@uniba.it.
authors.forename: Vito
authors.initials: V
authors.lastname: Martella
authors.forename: Pierfrancesco
authors.initials: P
authors.lastname: Pinto
authors.forename: Fabio
authors.initials: F
authors.lastname: Tummolo
authors.forename: Simona
authors.initials: S
authors.lastname: De Grazia
authors.forename: Giovanni M
authors.initials: GM
authors.lastname: Giammanco
authors.forename: Maria C
authors.initials: MC
authors.lastname: Medici
authors.forename: Balasubramanian
authors.initials: B
authors.lastname: Ganesh
authors.forename: Yvan
authors.initials: Y
authors.lastname: L'Homme
authors.forename: Tibor
authors.initials: T
authors.lastname: Farkas
authors.forename: Ferenc
authors.initials: F
authors.lastname: Jakab
authors.forename: Krisztián
authors.initials: K
authors.lastname: Bányai
mesh_terms: D016000:Cluster Analysis; D019295:Computational Biology; D015321:Gene Rearrangement; D005838:Genotype; D006801:Humans; D001257:Mamastrovirus / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D014764:Viral Proteins