Messenger RNA transport and HIV rev regulation

Article Abstract:

The mechanism of transport of messenger ribose nucleic acid (mRNA) molecules from the nucleus of the cell where they are synthesized from genes, to the cytoplasm of the cell, where proteins are synthesized from them, is not understood. RNA is modified in many different ways before it is transported. The processing that occurs is unique to mRNA, and appears to involve the regulation of the transport of molecules. RNA combines with proteins to form nuclear ribonucleoprotein complexes, and known complexes have been found in certain regions of the cell. An example of a modification that occurs to the mRNA is splicing, where regions of RNA that do not code for proteins are removed from the genetic information. Splicing involves the formation of a complex, known as the spliceosome. The spliceosome appears to associate with the nuclear matrix and the mRNA is thought to be transported through some type of matrix channels. Thus, RNA splicing and RNA transport appear to be connected. Studies with the human immunodeficiency virus type-1 (HIV-1), a type of retrovirus, or RNA virus, give further evidence for the connection between modification and transport. Production of different mRNA from the HIV-1 genome occurs at different times during viral infection. At first, mRNA that codes for molecules involved in the regulation of other processes is transported from the nucleus. The peptide rev binds to a particular RNA sequence, causing the inhibition of splicing. For viral replication to occur, it is necessary that molecules of RNA that are not spliced are transported to the cytoplasm of the cell, because new viruses are made from the unspliced RNA. Thus, the binding of the rev protein on RNA allows unmodified RNA to be transported to the cytoplasm of the cell. This example shows the complexity of RNA modification and transport. It also offers a possible approach to stop viral replication, and thus infection, by inhibiting the rev peptide. (Consumer Summary produced by Reliance Medical Information, Inc.)

HIV (Viruses), HIV, RNA, Retroviruses, Virus replication, RNA viruses

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Visualizing the logic behind RNA self-assembly

Article Abstract:

Jamie Cate et al have solved the structure of a 160-nucleotide catalytic RNA molecule. One surprise was the existence of a small recurring nucleotide combination, named the A-A platform, withing larger recurring motifs. The work will advance understanding of RNA splicing and protein synthesis.

Catalytic RNA

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Introns and the origin of protein-coding genes

Article Abstract:

Arlin Stoltzfus and his collegaues accurately concluded that it is unlikely that split genes appeared early in evolution through the recombination of mini-genes. but their analysis of the issue contains errors and fails to explain important evidence.

Introns, Chemical evolution, Molecular evolution

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