CSM News Electronic Edition Volume 2, number 10 March 5, 1994 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. Position Available ------------------- Postdoctoral opening at Virginia Tech University- Funds are available from an NIH-sponsored project to study the mechanism of glycogen phopshorylase (gp2) gene regulation in Dictyostelium. The goals include (1) site-directed mutagenesis and deletion analysis of the gp2 promoter to confirm the role of sequence elements in transcriptional regulation, and (2) cloning and/or purification of transcription factors for the gp2 promoter. Experience with techniques and procedures to investigate these questions is desirable. Virginia Tech University is located in the Blue Ridge mountains of Virginia, an area known for its scenic beauty, and is located 4-5 hours from Washington DC, Virginia Beach, and North Carolina's outer banks. Additional information can be obtained from Dr. Charles L. Rutherford, 2031 Derring Hall, Virginia Tech University, Blacksburg Virginia, 24061; phone 703-231-5349; FAX 703-231-9307, or rutherfo@vtvm1.cc.vt.edu ========== Abstracts ========== Characterization of a novel Dictyostelium discoideum prespore-specific gene, PspB, reveals conserved regulatory sequences Jo Anne Powell-Coffman and Richard A. Firtel Department of Biology Center for Molecular Genetics University of California, San Diego 9500 Gilman Dr. La Jolla, CA 92093-0634 tel. (619) 534-2788 fax (619) 534-7073 Development, in press. ABSTRACT While Dictyostelium discoideum has been studied as a developmental system for decades, and many regulatory proteins have been cloned, the molecular mechanisms of cell-type-specific gene expression are poorly understood. In this paper we characterize a novel prespore gene, PspB, and undertake a comparative analysis of the regulatory regions in prespore-specific D. discoideum promoters. Sequence alignment of the PSPB gene product with other prespore-specific proteins identifies a conserved, repeated 12 amino acid cysteine-containing motif that may be involved in spore coat function or assembly. Analysis of the PspB promoter identifies two domains essential for developmentally-induced promoter activity. The first region includes two CA-rich elements (CAEs) that we show to be functionally homologous to the cAMP-inducible elements previously identified in the SP60 (cotC) promoter. The PspB CAEs compete with the SP60 (cotC) CAEs for binding in vitro to a developmentally-regulated nuclear activity. We identify this activity as G-box Binding Factor, a developmentally-induced transcription factor. The PspB CAEs and adjacent nucleotides direct a very low level of prespore-enriched expression, but high levels of cell-type-specific expression requires a second promoter region: a 46-bp AT-rich sequence that does not resemble the CAEs or any other previously-described late gene promoter elements. Comparison of the PspB AT element with regulatory regions of the SP60 (cotC), SP70 (cotB), and D19 (pspA) promoters reveals an extensive consensus sequence. We suggest that these AT-rich sequences may represent a common regulatory element (or elements) required for prespore gene activation. ------------------------------------------------------------------- [End CSM News, volume 2, number 10]