title: In vitro cleavage of the simian virus 40 early polyadenylation site adjacent to a required downstream TG sequence.
abstract: Exogenous RNA containing the simian virus 40 early polyadenylation site was efficiently and accurately polyadenylated in in vitro nuclear extracts. Correct cleavage required ATP. In the absence of ATP, nonpoly(A)+ products accumulated which were 18 to 20 nucleotides longer than the RNA generated by correct cleavage; the longer RNA terminated adjacent to the downstream TG element required for polyadenylation. In the presence of ATP analogs, alternate cleavage was not observed; instead, correct cleavage without poly(A) addition occurred. ATP-independent cleavage of simian virus 40 early RNA had many of the same properties as correct cleavage including requirements for an intact AAUAAA element, a proximal 3' terminus, and extract small nuclear ribonucleoproteins. This similarity in reaction parameters suggested that ATP-independent cleavage is an activity of the normal polyadenylation machinery. The ATP-independent cleavage product, however, did not behave as an intermediate in polyadenylation. The alternate RNA did not preferentially chase into correctly cleaved material upon readdition of ATP; instead, poly(A) was added to the 3' terminus of the cleaved RNA during a chase. Purified ATP-independent cleavage RNA, however, was a substrate for correct cleavage when reintroduced into the nuclear extract. Thus, alternate cleavage of polyadenylation sites adjacent to a required downstream sequence element is directed by the polyadenylation machinery in the absence of ATP.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000260:Adenoviruses, Human / Q000235:genetics; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D011061:Poly A / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics* / Q000378:metabolism; D013698:Templates, Genetic; D014158:Transcription, Genetic
chemical_list: D012367:RNA, Viral; D011061:Poly A; D000255:Adenosine Triphosphate