Our research plan follows the long range goals stated in the initial proposal. Specifically, we plan to: (1) Isolate the yeast histone genes on recombinant DNA plasmids. (2) Determine the organization of the yeast histone genes by renaturation kinetics, restriction mapping, and DNA sequencing. (3) Use the cloned histone genes to study control, both in the cell cycle and at the level of control sequences in the genes. (4) Use plasmids containing DNA galactose pathway to measure the timing of mRNA for each during the cell cycle. (5) Since it is now possible to fractionate poly(A) based on size (using the Sephadex LH 20-100/GLYME chromatography system) we will be able to follow the processing of poly(A) to determine if the (A)90 species is a precursor to the two smaller classes, as well as the dependence on protein synthesis for poly(A) shortening. (6) The presumed ribonucleoprotein particle can be further characterized as to (a) nature of the associated proteins; (b) translatability of the large RNA in vitro (in collaboration with Dr. J. Hopper); (c) possible processing of the RNA; and (d) fate of the particle in mutants (ts136) which fail to transport RNA at the restrictive temperature. This might allow one to dissociate processing in the nucleus from transport to the cytoplasm.