Worm Breeder's Gazette 7(2): 26

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.

No 5-methylcytosine in C. elegans DNA

J. Laufer, S. Powers, B. Wood

Methylation of DNA has been implicated in gene regulation.  About 4% 
of the cytosine residues are methylated in mammalian DNAs, and some 
specific changes in methylation are correlated with changes in gene 
activity (e.g., McGee & Ginder, Nature 280, 419, 1979).  On the other 
hand, it was recently reported that Drosophila DNA contains no 5-
methylcytosine (News & Views, Nature 290, 363, 1981).  We undertook to 
determine whether C.  elegans DNA contains methylated bases by 
reversed-phase high pressure liquid chromatography of L1 DNA 
hydrolyzed to free bases with formic acid.  We detected no 5-
methylcytosine or N5-methyl adenine.  By comparison with hydrolyzed 
calf thymus DNA run on the same column, we can place an upper limit 
for 5-methylcytosine in C.  elegans DNA at about 0.01% of total 
nucleotides, corresponding to <0.04% of cytosine residues.