RNA processing.

Significant progress has been made over the last year in our understanding of the roles that RNA-binding proteins play in pre-mRNA splicing, the components of the spliceosome and how these components relate to the mechanism of splicing. Of particular importance has been the sequence analysis of the first mammalian splicing factors and structural determination of an RNA-binding domain.     

RNA editing.

Since its discovery, RNA editing in kinetoplastid mitochondria has proven a fascinating topic of study, and the last one and a half years have witnessed enormous advances in our understanding of this unprecedented form of RNA processing. The information flow in this RNA editing, once considered a candidate for defying the central dogma, is now known to conform to the DNA-to-RNA-to-protein paradigm, with the novel feature that the sequence of an edited region is not actually present in any DNA segment, but instead derives by a novel micro-interdigitating of information encoded in multiple DNA regions.     

Evidence that immune RNA is messenger RNA.

Exposure of rabbit spleen cell cultures to i-RNA isolated from T2 phage-exposed rabbit peritoneal exudate cells induces the synthesis of antigen and allotype specific 19S proteins even in the presence of actinomycin D. The same i-RNA directs the synthesis of proteins with comparable properties in cell-free extracts prepared from mouse L cells, indicating that i-RNA functions as mRNA and contains the information required to code for the synthesis of IgM antibodies.