Leader arrangement in the adenovirus fiber mRNA

Four oligonucleotides, complementary to the adenovirus 2 (ad2) fiber mRNA were chemically synthesized and used as primers to study the 5' end of that messenger. The oligonucleotides which were 8, 10, 12, and 14 nucleotides long had a common 3'-terminal sequence, TAC, complementary to the initiating codon of the fiber mRNA. The 5'-32P-labeled oligonucleotides were hybridized to polyadenylated mRNA from ad2-infected cells and the primer was extended, using reverse transcriptase. When the resulting products were analyzed by polyacrylamide gel electrophoresis multiple distinct bands could be identified by autoradiography. The extension products were characterized by hybridization and sequence analysis. The most prominent band contained the well-known tripartite lead which is attached to many different late adenovirus mRNAs. In addition, four differently spliced leaders were characterized which, besides the three segments of the tripartite leader, contain one or two auxilliary segments. A kinetic analysis of the different leaders during lytic adenovirus infection shows no temporal variation.