9 Supplement

Abstract

At a stage in the game when further surprises in the molecular biology of adenoviruses did not seem likely, remarkable developments have taken place on several fronts, giving fresh insights into control of the productive cycle. These represent, in part, logical extensions of preexisting lines of inquiry and, in part, the fruits of innovations in diverse areas such as recombinant DNA methodology and cell-free systems for transcription and replication.

Additional Early Products
Through application of improved techniques for the selection by hybridization (McGrogan et al. 1979; Ricciardi et al. 1979) and cell-free translation (Pelham and Jackson 1976) of mRNA, several novel early proteins have been discovered. These are indicated in Figure S9.1 together with their map positions insofar as they can be deduced from the locations of the various genomic DNA fragments to which they hybridize. Many of these products map in a segment of the genome that gives rise to the well-studied late leaders but had hitherto been considered silent as far as protein-coding capacity is concerned.

In most cases the detailed structures of these RNAs have not yet been established. However, it is already clear that many of them are unusual, even by adenovirus standards. For example, the species that most probably encode the 75K, 87K, and 105K polypeptides are leftward-reading and originate at position 75, apparently at the same promoter used for the early form of the mRNA for the 72K protein. They have leaders from this position, as well as from coordinates 68 and 39, coupled...