7-2/MRP RNAs in plant and mammalian cells: association with higher order structures in the nucleolus.

摘要: Abstract Mammalian MRP (for mitochondrial RNA processing) RNA, also known as 7-2 is a nuclear encoded small which has been reported to function in two different cellular compartments: the mitochondria and nucleus. The ribonucleoprotein particle contains 7-2/MRP called RNase MRP, ribonucleolytic activity shares some structural similarity with P. It proposed that mitochondria, responsible for endonucleolytic cleavage of primer during DNA replication. We have characterized gene cDNAs encoding 7-2/MRP-like Arabidopsis tobacco, found plants this enriched nucleoli but undetectable purified isolated from tobacco leaves or cells grown suspension. In glycerol gradients cosediments large approximately 80S structures possibly representing ribosomal precursors. Fractionation HeLa revealed resides nucleolus most it associated complexes sedimenting at 80S, similar those containing U3 nucleolar participate pre-rRNA processing. These results indicate ribonucleoparticle may be involved ribosome biogenesis, both plant mammalian cells.