CHARACTERIZATION OF 2 NEW CUTICULAR GENES SPECIFICALLY EXPRESSED DURING THE POST-ECDYSIAL MOLTING PERIOD IN TENEBRIO-MOLITOR

In a previous study, we have isolated a cDNA, TM-ACP17, coding for a p ost-ecdysial adult protein of Tenebrio molitor. After screening of a g enomic library with TM-ACP17, we report isolation and sequencing of TM -ACP17 gene and a new gene, TM-LPCP29, coding for a larval-pupal prote in. These two genes exhibit a common sequence of 15 nucleotides and a characteristic of most cuticular protein genes so far described: an in tron interrupting the signal peptide. The deduced aa sequence of TM-LP CP29 exhibits a high percentage of Ala (26.5%) and Val (17.5%) and is highly hydrophobic. In the N-terminal part, the motif VAAPV is repeate d ten times. Numerous histidine residues are present in the C- and N-t erminal regions. A comparison is made with other cuticle protein seque nces. Northern hybridization analysis showed that TM-LPCP29 is present during larval and mainly pupal post-ecdysial cuticle secretion. In-si tu hybridization revealed that TM-LPCP29 mRNA is expressed in epidermi s and not in muscles or fat body. (C) 1998 Elsevier Science B.V. All r ights reserved.