Worm Breeder's Gazette 10(2): 107

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.

Numerous Homeobox Containing Genes from Caenorhabditis elegans

Nancy Hawkins and Jim McGhee

Figure 1

Like everyone else, we were convinced that worms should have as many 
homeobox containing genes as other organisms.  Rather than continue 
with low stringency hybridizations with heterologous probes, we 
synthesized an oligonucleotide probe, using the worm codon bias, based 
on the most conserved sequence of known homeoboxes.  This region, from 
amino acid 44 55, is the second helix of the helix- turn- helix region 
i.e.  the putative DNA binding domain.  Screening a genomic Southern 
with this probe showed seven strongly hybridizing bands that remained 
after high stringency washing.  Numerous positive clones were then 
isolated from a genomic library.  One of these clones, JM#L1001, was 
mapped by Alan Coulson to the left end of the X chromosome.  Two other 
positive clones have not yet found a home in the genome.  The first 
clone was sequenced and shown to contain a homeobox domain with 50% 
amino acid homology to Antennapedia.  The 'homeobox' contains two 
introns based on estimates of splice-donor acceptor sites; one 47bp 
long between amino acids 21 and 22 and a second 48bp in length between 
amino acids 44 and 45.  The homeobox domain is contained within a 
putative open reading frame of 190 amino acids.
[See Figure 1]
In RNA extracted from a total worm population,three different 
message sizes are apparent: a l.3kb species and two smaller species, 
approximately 800 and 600bp.  The l.3kb message appears to be enriched 
in the poly A- fraction.  The different species seems to be 
developmentally regulated but much more work is needed.  We are now in 
the process of isolating the remaining homeobox containing genes.  It 
will be interesting to see if the mec-3 gene will be isolated in the 
screen,since the Way-Chalfie sequence is only 69% homologous to our 

Figure 1