Morphogenesis of the tail of bacteriophage lambda I. In vitro intratail complementation.

By studying nonsense mutants in ten of the 11 known tail genes of bacteriophage lambda we obtained the following results. Concentrated tail(-)-lysates complement each other in nearly all possible (45) combinations. The efficiency of complementation is very dependent on physical parameters (lysis procedure, concentration, temperature) and on the mutants used for complementation (i.e., type of precursors present, absence or presence of abortive structures, polarity effects of some nonsense mutants). Gene product dosage experiments, in which the ratio of concentrations of the different precursors present in different lysates is varied up to four orders of magnitude, allow us to distinguish five classes of intratail complementations. By these studies we detected that the morphogenetic action of at least two gene products, pV and pM, is extremely concentration-dependent. Furthermore the gene product dosage experiments allow us to deduce for five gene products the following sequence of morphogenetic action during lambda tail assembly: (pJ,pM), (pV,pU), pZ. Finally, we find that our in vitro complementation data are consistent with already known polarity properties of nonsense tail(-)-mutants of phage lambda.