reductase (DHFR) pre-mRNA processing and/or nuclear mRNA stability in methotrexate-resistant KB cells. Long-term exposure to FUra had no effect on the level of DHFR pre-mRNA containing certain introns, which are sections of pre-mRNA that are usually cut out of the sequence as a part of processing. However, levels of total DHFR mRNA decreased two-fold in cells exposed to 1.0 μM FUra. There was no significant change in the half-life, which refers to the time it takes 50% of the mRNA to decay, of total DHFR mRNA or pre-mRNA observed in cells exposed to FUra. And nuclear/cytoplasmic RNA labeling experiments demonstrated that the rate of nuclear DHFR RNA changing to cytoplasmic DHFR mRNA decreased in cells treated with FUra. These results provide further evidence that FUra may help in the processing of mRNA precursors and/or affect the stability of nuclear DHFR mRNA. Judith Lengyel and Sheldon Penman from the department of Biology at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts wrote an article about one type of primary transcript involved in the genes of two dipterans, or insects that have two wings: Drosophila and Aedes. The article describes how researchers looked at hnRNA, or basically pre-mRNA, primary transcripts in the two kinds of insects. The size of hnRNA transcripts and the fraction of hnRNA that is converted to mRNA in cell lines, or groups of cells derived from a single cell of whatever one is studying, of Drosophila melanogaster and Aedes albopictus were compared. Both insects are dipterans, but Aedes has a larger genome than Drosophila. This means that Aedes has more DNA, which means more genes. The Aedes line make larger hnRNA than did the Drosophila line even though the two cell lines grew under similar conditions and produced mature or processed mRNA of the same size and sequence complexity. These data suggest that the size of hnRNA increases with increasing genome size, which is obviously shown by Aedes. Ivo Melcak, Stepanka Melcakova, Vojtech Kopsky, Jaromıra Vecerova and Ivan Raska from the department of Cell Biology at the Institute of Experimental Medicine, at the Academy of Sciences of Czech Republic in Prague studied the influences of nuclear speckles on pre-mRNA. Nuclear speckles (speckles) are a part of the nuclei of cells and are enriched with splicing factors known for involvement in mRNA processing. Nuclear speckles have shown to serve neighboring active genes as storage places of these splicing