Worm Breeder's Gazette 15(2): 25 (February 1, 1998)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Neuronal specific bsh homeobox gene needs a home, inquire within.

Brian Harfe1, Andrew Fire2

1 Carnegie Institution of Washington, Department of Embryology, Present address: Emory University Biology Department, E-mail: bharfe@biology.emory.edu
2 Carnegie Institution of Washington, Department of Embryology

        Over the last several years we have been characterizing the NK-2
homeodomain family in C. elegans. During the course of this work we have
also studied a related homeobox gene, since named ceh-29. CEH-29 is a
member of the bsh (brain specific homeobox) family (thanks to T. Burglin
for help in classification). The founding member of this family,
Drosophila bsh, is expressed exclusively in the brain where it is
thought to play a highly specialized role in the determination and
function of brain cell types (Jones and McGinnis, 1993). ceh-29 was
initially identified by the genome sequencing project. The gene maps to
chromosome II (cosmid F31E8) between dpy-10 and cyp-10 with the gene
snt-1 located ~7kb downstream.
        As a starting point in our analysis of ceh-29 we used phage
libraries to isolate genomic DNA and a putative full length cDNA. The
cDNA clone allowed us to determine that CEH-29 was a relatively small
protein (190aa), containing a homeodomain and a number of acidic
regions. To determine where the ceh-29 promoter was active, we created
ceh-29::gfp and lacZ fusions. In transgenic lines, reporter expression
was first detected during early embryogenesis (~100 cells) in what
appeared to be neuronal precursors. Reporter expression continued in
neuronal cells reaching very high levels. In early larval development,
cell proccesses of numerous neural cells could be clearly observed. 
        To determine the consequences of loss of function of ceh-29, we
carried out ceh-29 RNAi in wild-type animals.  The F1 offspring of
injected animals were then scored for visible phenotypes. In these
animals we observed a low penetrance L1 scrawny arrest phenotype, with
the majority appearing wild-type 
        We have not characterized this gene further. Anyone interested
in analyzing the neuronal ceh-29::gfp expression pattern, or further
investigating the ceh-29 loss of function phenotype should contact us.

B. Jones and W. McGinnis (1993). A new Drosophila homeobox gene, bsh, is
expressed in a subset of brain cells during embryogenesis. Development
117, 793-806.