Molecular Weight Determination of Nucleic Acids by Gel Electrophoresis in Non-aqueous Solution

IN most areas of research concerned with the structure, function and synthesis of nucleic acids the measurement of molecular weights plays an inescapable part. There are many instances of problems hinging on a rather precise knowledge of the molecular weight of a nucleic acid; examples of particular current interest concern both animal and viral messengers, which are larger than can be accounted for by the total protein message that they encode and ribosomal-RNA, the molecular weight of which bears on the question of the stoichiometry of ribosomal components. Unfortunately the classical methods of molecular weight determination present great difficulties. The quantities of material required are frequently outside the range of feasibility. Moreover, the non-ideality in these highly charged molecules and polydispersity^1,2 resulting from contamination with minor cellular components, or commonly products of nuclease degradation (as well as the need to determine the partial specific volume), combine to make molecular weight measurement a major research undertaking. The remarkable spread of published values for widely studied RNA species reflects these problems.