Single stranded RNA genome

The human immunodeficiency vims (HIV) is the causative agent of the acquired immunodeficiency syndrome (AIDS). HIV is a retrovirus, whose replication includes the transcription of the single-stranded RNA genome into double stranded DNA (reverse transcription) and the covalent insertion of the DNA... 

The hepatitis delta virus (HDV) ribozyme is part of the circular single stranded RNA genome of the hepatitis delta virus which consists of a total of 1700 nucleotides. The HDV ribozyme is required for the processing of multimers of the genomic linear RNA transcripts to unit length by catalyzing a transesterification reaction that results in self cleavage [23]. 

Almost all plant viruses and some bacterial and animal viruses have RNA genomes. These genomes tend to be particularly small. For example, the genomes of mammalian retroviruses such as HIV are about 9,000 nucleotides long, and that of the bacteriophage Q/3 has 4,220 nucleotides. Both types of viruses have single-stranded RNA genomes. 

There are three groups of virus with a single-stranded RNA genome (ssRNA). The first group comprises viruses with RNA that functions both as genomic and messenger (for example, picornovirus and flavovirus). The ssRNA in these viruses is conventionally called positive-strand virus... 

As noted previously, enveloped animal viruses are surrounded by an outer phospholipid layer derived from the plasma membrane of host cells and containing abundant viral glycoproteins. The processes of adsorption and release of enveloped viruses differ substantially from these processes In nonenveloped viruses. To Illustrate lytic replication of enveloped viruses, we consider the rabies virus, whose nu-cleocapsld consists of a single-stranded RNA genome surrounded by multiple copies of nucleocapsld protein. Like... 

M FIGURE 4-41 Lytic replication cycle of rabies virus, an enveloped virus with a single-stranded RNA genome. The... 

Retroviruses are enveloped animal viruses containing a single-stranded RNA genome. After a host cell Is penetrated, reverse transcriptase, a viral enzyme carried In the virion, converts the viral RNA genome Into double-stranded DNA, which integrates into chromosomal DNA (see Figure 4-43). 

The NV is a human calicivims and contains a single-stranded RNA genome.Particles of NV have T=3 icosahedral symmetry with an approximate outer diameter of 38 nm and an average inner diameter of the central cavity that ranges from 20-29 nm. These virions contain 180 molecules of identical capsid protein (56.6 kl/)a each), which has two principle domains, S and P. linked by a flexible hinge.These viruses arc difficult to cultivate in tissue culture systems or animals,"" making them difficult to study, and this factor limits their use as nanosynthctic reaction vessels. 

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