RNA Terminal Phosphate Cyclase Domain Protein 1 (RTCD1)

RNA 3-prime-terminal phosphate cyclase (RPC) catalyzes the ATP-dependent conversion of a 3-prime phosphate to a 2-prime,3-prime-cyclic phosphodiester at the end of RNA.The deduced 366-amino acid protein has a calculated molecular mass of 39.4 kD. Northern blot analysis detected ubiquitous expression of 1.8- and 3.0-kb transcripts in human tissues and cell lines, although the ratio between the transcripts varied among tissues. Highest expression was in skeletal muscle. Immunofluorescence analysis localized epitope-tagged RPC primarily to the nucleus in HeLa cells and other mammalian cell lines. RPC is conserved among eukaryotes, bacteria, and archaea.Comparison of RNA and DNA substrates with identical sequences showed that the latter were 500-fold poorer substrates for RPC.