Temperature is a cue for gene expression in the post-infective L3 of the parasitic nematode Brugia pahangi

The temporal expression pattern of two genes, Bp-cdd and Bp-S3, was studied at defined points throughout the life cycle of Brugia pahangi. Both mRNAs were up-regulated to coincide with the transition of the L3 from the vector to the mammalian host. Bp-cdd was expressed almost exclusively in the post -infective (p.i.) L3 and L4 stages of the life cycle while Bp-S3 was also e xpressed in adult worms, but at a much lower level than in the larval stage s. Immunogold labelling with an antiserum raised to the recombinant Bp-CDD localised the native antigen to the hypodermis in the p.i. L3 and L4. Speci fic labelling was not detected in the adult worm. The expression of both mR NAs could be triggered by exposure of the vector-derived L3 to a simple mam malian culture system. Analysis of the factors, which induced expression su ggested that the temperature shift which accompanies the transition from mo squito to mammal was the most important cue for expression of both genes. ( C) 2001 Elsevier Science B.V. All rights reserved.