Abstract
The major 3'-5' pathway of RNA degradation in eukaryotic cells involves the exosome, which is a multi-protein complex of exoribonucleases. The exoribonucleases within this complex are highly conserved and are closely related to prokaryotic ribonucleases. We have identified and characterised the expression pattern of Drosophila tazman (taz), a component of the exosome which is closely related to Escherichia coli RNaseR and yeast Rrp44p. The tazman transcripts are differentially expressed during development, with maximum expression levels in 6-8 hr embryos. In situ hybridisation and immunolocalisation experiments show that tazman transcripts and protein are maternally derived, and are expressed ubiquitously throughout the embryo, with high levels in germ band and head structures. Differential expression of TAZ is likely to reflect changes in the activity of the 3'-5' mRNA turnover pathway which could have a major impact of the expression of target RNAs.
