Alkali-labile structures linked to the 5' ends of Bacillus subtilis short DNA chains

Alkali-labile portion covalently linked to the 5' ends of Bacillus subtilis short DNA chains, the putative primer RNA for discontinuous DNA synthesis, was isolated and analyzed using a temperature sensitive DNA polymerase I mutant, which accumulates nascent DNA fragments at a restrictive temperature. A novel oligonucleotide structure as well as mono- to triribonucleotide stretches were isolated at the 5' end of the short DNA chains. A structure for the novel oligonucleotide is proposed to be p5' X3' pp5' rN, where X represents unidentified nucleoside with a peculiar property. Possible metabolic relationship between these molecules and primer RNA has been discussed.