Dicty News Electronic Edition Volume 22, number 1 January 23, 2004 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of Dicty-News, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. ============= Abstracts ============= Analyses of cDNAs from growth and slug stages of Dictyostelium discoideum Hideko Urushihara, Takahiro Morio, Tamao Saito, Yuji Kohara, Eiko Koriki, Hiroshi Ochiai, Mineko Maeda, Jeffrey G. Williams, Ikuo Takeuchi, and Yoshimasa Tanaka Nuc. Acids Res., in press Dictyostelium is a favored model for studying problems in cell and developmental biology. To comprehend the genetic potential and networks that direct growth and multicellular development, we are performing a large-scale analysis of Dictyostelium cDNAs. Here, we newly determine 7,720 nucleotide sequences of cDNAs from the multicellular, slug stage (S) and 10,439, from the unicellular, vegetative stage (V). The combined 26,954 redundant ESTs were computer assembled using the PHRAP pro-gram to yield 5,381 independent sequences. These 5,381 predicted genes represent about half of the estimated coding potential of the organism. One third of them were classified into 12 functional categories. Although the overall classification patterns of V and S libraries were very similar, stage-specific genes exist in every category. The majority of V-specific genes function in some aspect of protein translation, while such genes are in a minority in the S-specific and common populations. Instead, genes for signal transduction and multicellular organization are enriched in the population of S-specific genes. Genes encoding the enzymes of basic metabolism are mainly found in the common gene population. These results therefore suggest major differences between growing and developing Dictyostelium cells in the nature of the genes transcribed. Submitted by: HIDEKO URUSHIHARA [hideko@biol.tsukuba.ac.jp] ----------------------------------------------------------------------------- Dictyostelium macroautophagy mutants vary in the severity of their developmental defects. Grant P. Otto, Mary Y. Wu, Nevzat Kazgan, O. Roger Anderson, and Richard H. Kessin Journal of Biological Chemistry, in press Macroautophagy is the major mechanism that eukaryotes use to recycle cellular components during stressful conditions. We have previously shown that the Atg12-Atg5 conjugation system, required for autophagosome formation in yeast, is necessary for Dictyostelium development. A second conjugation reaction, Aut7/Atg8 lipidation with phosphatidylethanolamine, as well as a protein kinase complex and a phosphatidylinositol 3â-kinase complex, are also required for macroautophagy in yeast. In this study, we characterize mutations in the putative Dictyostelium discoideum orthologues of budding yeast genes that are involved in one of each of these functions, ATG1, ATG6 and ATG8. All three genes are required for macroautophagy in Dictyostelium. Mutant amoebae display reduced survival during nitrogen starvation and reduced protein degradation during development. Mutations in the three genes produceaberrant development with defects of varying severity. As with other Dictyostelium macroautophagy mutants, development of atg1-1, atg6- and atg8- is more aberrant in plaques on bacterial lawns than on nitrocellulose filters. The most severe defect is observed in the atg1-1 mutant, which does not aggregate on bacterial lawns and arrests as loose mounds on nitrocellulose filters. The atg6- and atg8- mutants display almost normal development on nitrocellulose filters, producing multi-tipped aggregates that mature into small fruiting bodies. The distribution of a green fluorescent protein fusion of the autophagosome marker, Atg8, is aberrant in both atg1-1 and atg6- mutants. Submitted by: Grant Otto [go25@columbia.edu] =============================================================================== [End Dicty News, volume 22, number 1]