THE SUPPRESSOR OF FORKED PROTEIN OF DROSOPHILA, A HOMOLOG OF THE HUMAN 77K PROTEIN REQUIRED FOR MESSENGER-RNA 3'-END FORMATION, ACCUMULATESIN MITOTICALLY-ACTIVE CELLS

The suppressor of forked (Su(f)) protein of Drosophila melanogaster is highly homologous to two proteins involved in mRNA 3'-end formation, the yeast RNA14 protein and the 77K subunit of human cleavage stimulat ion factor (CstF). This suggests a role for su(f) in mRNA 3'-end-proce ssing, probably as part of Drosophila CstF. We have investigated the e xpression pattern of su(f) during Drosophila development and found tha t the su(f) gene product is not detected ubiquitously. The Su(f) prote in accumulates in mitotically-active cells, but does not in non-dividi ng cells. This expression pattern corroborates earlier data suggesting that the phenotypes of su(f)? mutants could result from a defect in c ell proliferation. Our results suggest that, in Drosophila, Su(f) is i nvolved in the regulatory function of CstF. (C) 1998 Elsevier Science Ireland Ltd.