Studies of defective interfering (DI) RNAs of the murine coronavirus mouse hepatitis virus (MHV) suggest that a 69-nucleotide-long packaging signal is necessary for MHV genomic RNA packaging into MHV particles. In this study we showed that when RNA transcripts that consisted of a non-MHV sequence and the packaging signal were expressed in MHV-infected cells, they were packaged into MHV particles. Those RNA transcripts that lacked the packaging signal or those containing a mutated packaging signal did not package efficiently. Thus, the presence of the packaging signal was sufficient for RNA packaging into MHV particles. Packaging of viral genomic RNA into virus particles involves recognition and interaction of various molecules and is an essential step in the multiplication of any RNA virus. RNA packaging signals necessary for virus RNA packaging are described for several RNA viruses and hepadnaviruses (1, 5, 7, 11, 20, 27, 36, 37, 41, 42). Among these viruses, there are several examples in which the identified packaging signal is necessary and sufficient for viral RNA packaging (1, 7, 11, 42). The packaging signal(s) of some RNA viruses is mapped within more than one viral genomic region (20, 27, 36); for many viruses, it is not known whether a combination of multiple genomic regions or only one region is necessary for viral RNA packaging. Nor is it known if the packaging signal alone can suffice for viral RNA packaging. Coronaviruses are large enveloped viruses containing a long, single-stranded, positive-sense genomic RNA that cause a variety of diseases in humans and animals (35). A prototype coronavirus, mouse hepatitis virus (MHV), contains a 31 kblong MHV genomic RNA (17, 26). Other coronaviruses, such as infectious bronchitis virus (40), transmissible gastroenteritis virus (TGEV) (29), and bovine coronavirus (9), package virusspecific subgenomic RNAs as well as nonviral cellular RNA. Coronavirus contains four proteins, S, M, sM, and N protein; all except N protein are found in the virus envelope. S protein binds to host-cell receptors (38) and induces cell fusion (4). M protein, a triple-spanning transmembrane protein (2), is the most abundant glycoprotein. A minute amount of sM protein associates with MHV envelope (39). N protein and the genomic RNA form a helical nucleocapsid (21). Recently Risco et al. demonstrated that TGEV particles contain a spherical internal core, which seems to consist of mostly M protein and a lesser amount of N protein (28). They also showed that the helical nucleocapsid locates inside of the internal core (28). M protein and sM protein are necessary for packaging of viral nucleocapsid (12) and MHV envelope formation (3, 12, 34), while S protein is dispensable for both these functions (3, 12, 34). The MHV nonstructural proteins, includ

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High-resolution (0.6m) commercial satellite images contain a wealth of information for mapping earthquake damage. Satellite images of the city of Bam, acquired on 30 September 2003 (pre-earthquake) and 03 January 2004 (post-earthquake), were obtained and used to distinguish damage patterns across the city. Comparisons between pre- and post-earthquake images clearly show structural damage and collapse. Using spectral (color) and textural information from the post-earthquake image, regions of damage were identified using a semi-automated computer-based algorithm. This analysis indicates that the damage within the city of Bam was concentrated in the eastern sections of the city. The extent of damage in some sections of the city reached 100%. The results from this study not only provide information regarding damage patterns for the city of Bam, but they also illustrate the potential for using satellite images to understand and document earthquake effects during future earthquakes.

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