Screening of two Drosophila nervous system cDNA libraries with DNA pro
bes derived from lepidopteran prothoracicotropin (PTTH) did not yield
any hybridizing clone. Monoclonal antibody to Bombyx PITH recognized i
n the expression cDNA library several clones but their sequencing reve
aled relationship to elastins and collagens rather than to PTTH. We co
nclude that Drosophila PTTH cannot be identified with probes derived f
rom lepidopteran PTTH.