Unequal Distribution of N⁶-Methyladenosine in Influenza Virus mRNAs

Abstract

Influenza virus mRNA is posttranscriptionally methylated at internal adenosine residues to form N⁶-methyladenosine (m⁶A). It has been previously shown that there is an average of three m⁶A residues per influenza virus mRNA (R. M. Krug, M. A. Morgan, and A. J. Shatkin, J. Virol. 20:45-53, 1976). To determine the distribution of m⁶A in the different influenza virus mRNAs, we purified six of the mRNAs by hybrid selection, digested them with nuclease, and determined their methylation patterns by high-pressure liquid chromatography. The amount of m⁶A in the different mRNAs varied from one in matrix to eight in hemagglutinin.