Over 225,000 independent Agrobacterium transferred DNA (T-DNA) insertion events in the genome of the reference plant Arabidopsis thaliana have been created that represent near saturation of the gene space. The precise locations were determined for more than 88,000 T-DNA insertions, which resulted in the identification of mutations in more than 21,700 of the ∼29,454 predicted Arabidopsis genes. Genome-wide analysis of the distribution of integration events revealed the existence of a large integration site bias at both the chromosome and gene levels. Insertion mutations were identified in genes that are regulated in response to the plant hormone ethylene.

The nonstructural protein 1 (nsp1) of the severe acute respiratory syndrome coronavirus has 179 residues and is the N-terminal cleavage product of the viral replicase polyprotein that mediates RNA replication and processing. The specific function of nsp1 is not known. Here we report the nuclear magnetic resonance structure of the nsp1 segment from residue 13 to 128, which represents a novel ␣/␤-fold formed by a mixed parallel/antiparallel six-stranded ␤-barrel, an ␣-helix covering one opening of the barrel, and a 3 10 -helix alongside the barrel. We further characterized the full-length 179-residue protein and show that the polypeptide segments of residues 1 to 12 and 129 to 179 are flexibly disordered. The structure is analyzed in a search for possible correlations with the recently reported activity of nsp1 in the degradation of mRNA.After the major outbreak of severe acute respiratory syndrome (SARS) in the beginning of 2003, the SARS coronavirus (SARS-CoV) became a major topic of coronavirus research. The coronavirus genome is composed of a single plus-strand RNA of about 30 kb, which is the largest nonsegmented genome among known RNA viruses. About two-thirds of the coronavirus genome is devoted to encoding the replicase that mediates viral RNA synthesis (64). The replicase gene comprises two large open reading frames (ORFs) located at the 5Ј end of the genome. The first one, ORF1a, encodes a polyprotein of 450 to 500 kDa (polyprotein 1a), and the second one, ORF1b, is translated together with ORF1a after a Ϫ1 ribosomal frameshift, leading to the expression of the "polyprotein lab," which has a size of 750 to 800 kDa. The replicase polyprotein is processed by ORF1a-encoded viral proteinases, which leads to about 16 nonstructural proteins (nsp), which are numbered consecutively from the N terminus to the C terminus of the polyprotein (14,53).The large number of mature proteins produced from the polyprotein indicates a high level of complexity of the viral replication process. Some of the enzymatic activities that were detected or predicted in SARS-CoV to date include the main protease (nsp5), a papain-like proteinase (nsp3d; PLpro), an RNA-dependent RNA polymerase (nsp12), an RNA helicase (nsp13), an endoribonuclease (nsp15), an ADP-ribose-1Љ-phosphatase (nsp3b), a deubiquitinase (nsp3d), a 3Ј35Ј exoribonuclease (nsp14), and a ribose-2Ј-O-methyltransferase (nsp16) (3,5,18,21,22,44,59,70). For the two proteases, the endoribonuclease, and the ADP-ribose-1Љ-phosphatase, three-dimensional structures have been solved, which together with biochemical data have revealed some aspects of the enzyme mechanisms (27,54,56,58,63,67; reviewed in references 4, 35, and 65). The physiological functions of several of the other nonstructural proteins remain to be determined, but high-resolution structure determinations have allowed the identification of possible functional sites and provided the basis for further biochemical studies (15,30,52,61,62,68). Other replicase proteins still remain to be characterized.Nsp1 is the N-te...