A low molecular weight species of RNA synthesized early after induction of the prophage lambda

In the course of our studies on the messenger RNA of bacteriophage λ, a low molecular weight RNA, l1, synthesized very early after induction of the prophage, has been identified. It has been possible to obtain it in a very pure state through specific hybridization with the light strand of λ DNA. The results of two-dimensional electrophoresis of pancreatic ribonuclease and ribonuclease T1 digests indicate that l1 is a homogeneous species. Some of its properties were investigated to elucidate whether they were most similar to those of transfer RNA, 5 s RNA or messenger RNA. Although its electrophoretic mobility is similar to that of transfer RNA and 5 s RNA, it is definitely more unstable than these species and in this respect rather like messenger RNA. Its function is yet unknown.