Abstract
The use of bacteriophages as experimental tools allows the investigation of interactions between components at the molecular level that are often not possible in more complex virus systems. The bacteriophage φ29 acts as a molecular machine to package its own genomic DNA during viral assembly. Self-associating RNA molecules, called pRNA, have an essential role in the function of this machine. This paper reports the characterization of this self-association (which leads to multimerisation of wild-type and truncated variant pRNAs) by analytical ultracentrifugation (including determination of the partial specific volume of the pRNA), together with an investigation into the domains of the molecule important for multimerisation by the use of complementary DNA probes.