Developmental arrest inCaenorhabditis elegansdauer larvae causes high expression of enzymes involved in thymidylate biosynthesis, similar to that found inTrichinellamuscle larvae

Abstract

Crude extract specific activities of thymidylate synthase, dUTPase, thymidine kinase and dihydrofolate reductase were high during the development ofCaenorhabditis elegans, the dauer larva activities being similar to those previously determined inTrichinella spiralisandT. pseudospiralismuscle larvae (with the exception of thymidine kinase, not detected inTrichinella). High thymidylate synthase expression in developmentally arrested larvae, demonstrated also at the mRNA and protein levels, is in agreement with a global cell cycle arrest of dauer larvae and indicates this unusual cell cycle regulation pattern can be shared by developmentally arrested larvae ofC. elegansand the twoTrichnellaspecies. Hence, the phenomenon may be characteristic for developmentally arrested larvae of different nematodes, rather than specific for the parasiticTrichinellamuscle larvae. EndogenousC. elegansthymidylate synthase was purified and its molecular properties compared with those of the recombinant protein, expression of the latter inE. colicells confirming the NCBI database sequence identity.