Changes in gene expression associated with developmental arrest and longevity in Caenorhabditis elegans

Gene expression in a developmentally arrested, long-lived dauer Population of Caenorhabditis elegans was compared with a nondauer (mixed-stage) popula tion by using serial analysis of gene expression (SAGE). Dauer (152,314) an d nondauer (148,324) SAGE tags identified If,130 of the predicted 19,100 C elegans genes. Genes implicated previously in longevity were expressed abun dantly in the dauer library, and new genes potentially important in dauer b iology were discovered. Two thousand six hundred eighteen genes were detect ed only in the nondauer population, whereas 2016 genes were detected only i n the dauer, showing that dauer larvae show a surprisingly complex gene exp ression profile. Evidence for differentially expressed gene transcript isof orms was obtained for 162 genes. HI histones. were differentially expressed , raising the possibility of alternative chromatin packaging. The most abun dant tag from dauer larvae (20-fold more abundant than in the nondauer prof ile) corresponds to a new, unpredicted gene we have named tts-1 (transcribe d telomere-like sequence), which may interact with telomeres or telomere-as sociated proteins. Abundant antisense mitochondrial transcripts (2% of all tags), suggest the existence of an antisense-mediated: regulatory mechanism in C elegans mitochondria. In addition to providing a robust tool for gene expression studies, the SAGE approach already has provided the advantage o f new gene/transcript discovery in a metazoan.