title: An in vivo recombinant RNA capable of autocatalytic synthesis by Q beta replicase.
abstract: A variety of small RNAs ranging from tens to hundreds of nucleotides in length grow autocatalytically in a Q beta replicase (Q beta phage RNA-dependent RNA polymerase) reaction in the absence of added template, and similar RNAs are found in Q beta phage-infected Escherichia coli cells. Three such RNAs have been sequenced. One of them that is 221 nucleotides (nt) long ('MDV-1' RNA) has been found to be partially homologous to Q beta phage RNA 8, which might be considered as an indication of its origination from by-products of the Q beta RNA replication. To gain further insight into the origin and function of these RNAs, we have sequenced a new RNA, 120 nt long, isolated from the products of spontaneous synthesis by the nominally RNA-free Q beta replicase preparation. The minus strand of this RNA appeared to be a recombinant RNA, composed of the internal fragment of Q beta RNA (approximately 80 nt long) and the 33-nt-long 3'-terminal fragment of E. coli tRNA(1Asp). This seems to be the first strong indication of RNA recombination in bacterial cells. The various implications of this finding are discussed.
mesh_terms: D001483:Base Sequence; D002474:Cell-Free System; D003090:Coliphages / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011777:Q beta Replicase / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012328:RNA Viruses / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000378:metabolism*; D012349:RNA, Transfer, Asp / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D012329:RNA, Bacterial; D012349:RNA, Transfer, Asp; D012367:RNA, Viral; C039919:RNA, recombinant; D014764:Viral Proteins; D012313:RNA; D011777:Q beta Replicase; D012316:RNA Nucleotidyltransferases