CSM News Electronic Edition Volume 1, number 22 November 20, 1993 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to CSM-News@worms.cmsbio.nwu.edu. Back issues of CSM-News, the CSM Reference database and other useful information is available by anonymous ftp from worms.cmsbio.nwu.edu [129.105.233.50], via Gopher at the same address, or by World Wide Web through WWW.acns.nwu.edu. =================== Positions Available =================== Positions available for Diplomarbeit (stud. HK) PhD Thesis (Bat IIa/2) Postdoc (Bat IIa) on DFG funded projects (nucleo-cytoplasmic transport of nucleic acids, RNA biochemistry, molecular genetics of morpho-regulatory processes). more information in recent publications: Guddat et al. (1990) Cell 60, 619-628 Nietfeld et al. (1990) EMBO J. 9, 3699-3705 El-Bardi et al. (1991) EMBO J. 10, 1407-1413 Koester et al. (1991) EMBO J. 10, 3087-3093 Van Wijk et al. (1992) Mech. Dev. 39, 63-72 Theunissen et al. (1992) Cell 71, 679-690 Theunissen and Pieler (1993) TIBS 18, 226-230 Nietfeld et al. J. Mol. Biol. 230, 400-412 If interested contact Dr. Tomas Pieler Univ. Goettingen Inst. f. Biochemie u. Mol. Zellbiol. Humboldtallee 23 D-37073 Goettingen Tel.: 0551-395683 FAX 0551-395960 no e-mail address available yet! ====== REMI ====== Angelika Konzok and Wolfgang Nellen write: A general and a specific question concerning remi mutants: 1. what happens to mutants one has identified but does not really care about? I think it would be a waste to throw them out. A suggestion would be to advertise them on the network and sell them for the best offer. If nobody is interested, should we have a central storage which also lists how far these things have been characterized? 2. the question came up because we have some which might be of interest to others (one stops e.g. at tight agg, one makes small colonies). We might still look at the DNA but will then stop because we are interested in other things. If REMI mutants are sent out to other groups to play with, how can we avoid that a whole bunch of people try to do the same thing with them? [[This would be a good topic to discuss via the e-mail distribution list-- send your messages to dd-email-list@worms.cmsbio.nwu.edu. A note about answering questions posted on the list: Please don't just use the "reply" option of your email program--that will send the message to just the person who wrote it. Instead send it to the dd-email-list address. That way we'll all see the answers. --Rex]] ============ ABSTRACTS ============ "Nucleotide Sequence of Ddp1, a High Copy Number Nuclear Plasmid of Dictyostelium discoideum." Nigel A. Farrar(1,3), Hidenori Kiyosawa (2), Joanne E. Hughes (2), Dennis L. Welker (2) and Keith L. Williams (1) 1. School of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia, 2. Molecular Biology Program,. Biology Department, Utah State University, Logan, Utah 84322-5500, USA, 3. Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK PLASMID, in press Summary The complete nucleotide sequence of Ddp1, a high copy number 13.7 kbp endogenous nuclear plasmid of Dictyostelium discoideum is presented. Previous studies have shown nine transcripts which map to five different regions of Ddp1, suggesting alternative transcription initiation sites and/or post transcriptional processing. The sequence presented here shows five long open reading frames corresponding to previously known transcribed regions, as well as an additional reading frame, in the region of the presumed origin of replication. Two of the predicted proteins from the Ddp1 reading frames have potential leader sequences and transmembrane domains, while the rest, if translated, would encode soluble proteins. One of these has both leucine zipper and zinc finger-like motifs. Sequences upstream of the reading frames show strong similarities to chromosomal promoter elements, suggesting that transcription of at least some of the plasmid-encoded genes is regulated by factors which regulate chromosomal transcription in this organism. The region containing the presumptive origin of replication contains the promoters of the major growth-specific gene, as well as a second gene; thus the processes of transcription and replication of Ddp1 may be intimately linked. The origin-encompassing region has a long homopurine/homopyrimidine stretch, which is similar to sequences shown in vitro to be capable of forming a triple helix structure through Hoogsteen base pairing. Possible roles for these sequences and the products of the ORFs in plasmid maintenance are discussed. ------------------------------------------------------------- Cooperation of positively and negatively acting promoter elements determines prespore-specific transcription of Dp87 gene in Dictyostelium. Takahiro Morio (1,*), Ikuo Takeuchi (1) and Masao Tasaka (1,2) (1) Division of Developmental Biology, National Institute for Basic Biology, Okazaki 444, Japan. (2) Department of Botany, Faculty of Science, Kyoto Univ., Kyoto 606-01, Japan. (*) Present address: Institute of Biological Sciences, Univ. of Tsukuba, Tsukuba, Ibaraki 305, Japan. Mechanisms of Development, in press Summary Dp87 gene in Dictyostelium is a novel prespore-specific gene, whose expression is first observed when aggregation stream is formed, the earliest among prespore-specific genes so far isolated. By 5'- sequential deletion analyses, we had previously indicated that the region between -447 and -356 is important for transcription. In this study, we show by detailed analyses that the promoter of this gene consists of at least four regulatory regions with distinct functions as follows: (1) prespore-specific positive regulatory region between -666 and -158 including the previously identified cis-acting region (regions A-D), (2) negative regulatory region between -157 and -94 effective in growing and prestalk cells (region E), (3) general positive regulatory region between -93 and -63 (region F) and (4) the region between -62 and +9 including putative TATA box and the start site of transcription, which is required for proper regulation through the upstream regulatory regions. ------------------------------------------------------------------- [[End CSM News, volume 1, number 22]]