Open AccessInitiator RNA in Discontinuous Polyoma DNA Synthesis
Author(s) -
Peter Reichard,
R. Eliasson,
Gunilla Söderman
Publication year - 1974
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.71.12.4901
Subject(s) - rna , nuclease protection assay , dna , rnase p , oligonucleotide , base pair , microbiology and biotechnology , biochemistry , nucleotide , biology , transcription (linguistics) , chemistry , rna dependent rna polymerase , gene , linguistics , philosophy
During replication of polyoma DNA in isolated nuclei, RNA was found attached to the 5′ ends of growing progeny strands. This RNA starts with either ATP or GTP and can be labeled at its 5′ end with32 P from β-labeled nucleotides. Digestion of progeny strands with pancreatic DNase released32 P-labeled RNA that, on gel electrophoresis, gave a distinct peak in the position expected for a decanucleotide. We believe that this short RNA is involved in the initiation of the discontinuous synthesis of DNA and propose the name “initiator RNA” for it. The covalent linkage of initiator RNA to 5′ ends of growing DNA chains was substantiated by the finding that32 P was transferred to ribonucleotides by alkaline hydrolysis of purified initiator RNA obtained by DNase digestion of polyoma progeny strands synthesized from [α-32 P]dTTP. While initiator RNA was quite homogeneous in size, it had no unique base sequence since digestion with pancreatic RNase of initiator RNA labeled at its 5′ end with32 P released a variety of different [32 P]oligonucleotides. The switch from RNA to DNA synthesis during strand elongation may thus depend on the size of initiator RNA rather than on a specific base sequence.