AN UNUSUAL LIAISON - SMALL NUCLEAR AND CYTOPLASMIC RNA GENES TEAM UP WITH TRANSFER-RNA GENES IN TRYPANOSOMATID PROTOZOA

The study of transcription has revealed a complex and diverse set of b iochemical interactions between sequence-specific DNA-binding proteins promoter and enhancer elements, and the basal transcriptional apparat us consisting of RNA polymerase and a variety of accessory factors. Ou r understanding of promoter structures and trans-acting factors in try panosomatid protozoa is at present quite limited but is clearly gainin g momentum. Only recently, through the advent of DNA transfection tech nology, has it become possible to identify the cis-acting DNA sequence s involved in gene expression in these organisms. Here, Valerian Nakaa r; Christian Tschudi and Elisabetta Ullu summarize some recent insight s into the structure and functioning of RNA polymerase iii transcripti on units coding for smell nuclear and cytoplasmic RNAs in trypanosomat id protozoa.