Worm Breeder's Gazette 7(1): 53

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.

C. elegans Histone Genes

D. Campanelli, M. Johnson, G. Childs, S. Emmons

We have begun an analysis of the structure of C. 
genes with the eventual goal of studying the 
regulation of their expression during development and of identifying 
mutants that affect histone gene expression. So far we have carried 
out preliminary mapping experiments on three phages carrying C. 
genes, and are in the process of studying 19 
others. Phages were isolated from a lambda1059 clone bank carrying 15 
kb Sau3A Bristol fragments, using as a probe a cloned sea urchin 
histone H4 gene. This probe hybridized to from five to more than ten 
fragments when N2 DNA was digested with various restriction enzymes, 
and the pattern of fragments was complex, with no indication of a 
tandem arrangement. Probes specific for each of the other four sea 
urchin histone genes gave similarly complex patterns on Southern 
hybridizations and it was not possible to deduce a simple map 
representing C. gene arrangement from 
multiple digestions of genomic DNA with combinations of enzymes.
More detailed analysis of three phages carrying cloned histone genes 
confirmed the non-tandem arrangement. Histone genes were found to be 
present on these phages in clusters, each cluster containing at least 
one copy of each of the five histone genes. Two of the phages had two 
such clusters and one a single one, and there was no evidence of 
repetition in the location of restriction sites through or between the 
clusters. We are presently studying the remaining 19 phages to 
identify the arrangement of the genes on them and to correlate each 
with bands on a Southern hybridization of genomic DNA, our goal at 
this stage being to clone all of the C. genes.
In its non-tandem, clustered arrangement of histone genes, C. 
sely resembles higher vertebrates than 
invertebrates such as sea urchin and Drosophila that have been most 
extensively studied to date.