David Roos. Interview by H. Craig Mak

Reflecting on the growth of bioinformatics over the past decade, the University of Pennsylvania's David Roos highlights the increasing diversity of large-scale data sets, changing paradigms for data release and the emergence of new career opportunities.     

NatC Nalpha-terminal acetyltransferase of yeast contains three subunits, Mak3p, Mak10p, and Mak31p

The yeast Saccharomyces cerevisiae contains three types of N(alpha)-terminal acetyltransferases, NatA, NatB, and NatC, with each having a different catalytic subunit, Ard1p, Nat3p, and Mak3p, respectively, and each acetylating different sets of proteins with different N(alpha)-terminal regions. We show that the NatC N(alpha)-terminal acetyltransferases contains Mak10p and Mak31p subunits, in addition to Mak3p, and that all three subunits are associated with each other to form the active complex. Genetic deletion of any one of the three subunits results in identical abnormal phenotypes, including the lack of acetylation of a NatC substrate in vivo, diminished growth at 37 degrees C on media containing nonfermentable carbon sources, and the lack of maintenance or assembly of the L-A dsRNA viral particle.     

Studies on the Chemical Constituents of Viola yedoensis Mak

The lipophilic and alcoholic fractions of V. yedoensis Mak., Six constituents were isolated and identified: palmitic acid, p-hydroxybenzoic acid, trans-p-hydroxycinnamic acid, butanedioic acid, violyedoenamide (tetracosanoyl-p-hydroxyphenethylamine) and afzelin (kaempferol-3- O-rhamnopyranoside). They were all isolated for the first time from V. vedoensis Mak., vio- lyedoenamide is a new compound.     

Mak mutants of yeast: mapping and characterization.

Killer strains of Saccharomyces cerevisiae are those carrying a 1.5 x 10(6)-dalton double-stranded (ds) ribonucleic acid (RNA) (M) in virus-like particles and secreting a protein toxin. Most yeast (koller or not) also carry a 3 x 10(6)-dalton dsRNA (L). We have mapped mutations in eight of the chromosomal genes needed for maintaining M (mak genes). The mak genes are widely distributed on the yeast map, with no multigene complexes. We show that mutants defective in these and other mak genes lose M dsRNA, but not L dsRNA. The mak3-1 mutation results in markedly decreased cellular levels of L dsRNA, but mak3-1 stains do not lose L dsRNA completely. Mutation of mak16 results in temperature-sensitive growth, whereas mutations in mak13, mak15, mak17, mak20, mak22, and mak27 result in slow growth at any temperature. No effect of mak mutations on mating, meiosis, sporulation, germination, homothallism, or ultraviolet sensitivity has been found. The specificity of mak mutations is discussed.