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Edited by Ulrike Kutay Keywords:Alternative polyadenylation 3 0 -UTR Pta1 Pcf11 Yeast a b s t r a c t This work reports the involvement of yeast RNA processing factors Pta1 and Pcf11 in alternative 3 0 -end RNA processing. The pta1-1 and pcf11-2 mutations changed the predominance of KlCYC1 1.14 and 1.5 kb transcript isoforms. Mutation of the KlCYC1 3 0 -UTR AU-rich sequence at positions 679-690 (mutant M1) altered transcript predominance. Moreover, expression of M1 in the yeast mutants partially suppressed their effects in the predominance pattern. The combination of the M1 and M2 (694-698 deletion) mutations abolished the alternative processing. Pta1 involvement in this selection was confirmed using the Pta1-td degron strain.

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PICDI is a very simple program designed to calculate the Intrinsic Codon Deviation Index (ICDI). The program is available in Macintosh as well a PC format. Requirements for correct input of the sequences have been kept to a minimum and the analysis of sequences up to 2000 codons is very quick. The ICDI is very useful for estimation of codon bias of genes from species in which optimal codons are not known. The availability of a computer program for its calculation will increase its usefulness in the fields of Molecular Biology and Biotechnology.

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Phosphofructokinase (PFK) from the mantle of Mytilus galloprovincialis Lmk. was purified 302-fold with a yield of 27%. The enzyme proved to be a 340,000-dalton oligomer comprising four identical 85,000-dalton subunits.Like other phosphofructokinases, the enzyme behaved cooperatively with fructose 6-phosphate and was inhibited by high concentrations of ATP.The fall in pH value produces a decrease of enzyme affinity for Fru 6-P and for the activator AMP, together with a greater inhibition by ATP.AMP, cyclic AMP, and fructose 2,6-bisphosphate increased the affinity of mussel mantle PFK for Fru 6-P and decreased the inhibition by ATP, while ammonium ions activated the enzyme increasing only the Vmax. Phosphoenolpyruvate acted as an inhibitor, decreasing the affinity of the enzyme for Fru 6-P