Asymmetric transcription of bacteriophage Mu-1

The deoxyribonucleic acid (DNA) of bacteriophage Mu-1 can be separated into its complementary strands by poly(U,G) binding and equilibrium centrifugation. DNA-ribonucleic acid (RNA) hybridizations in liquid show that more than 98% of "early" phage-specific RNA and over 96% of "late" messenger species bind to the heavy [poly(U,G)-binding] strand of Mu-1 DNA. A small (1.45%) but significant amount of late RNA binds to the light strand. The significance of this RNA fraction is discussed in connection with the peculiar structure of denatured and reannealed Mu-1 DNA.