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]