cDNA identification and gene expression of two types of acetylcholinesterases in a cultured cell line of Aedes albopictus, compared to mosquito whole body extracts

Abstract

Two cDNA sequences containing open reading frames encoding two types of acetylcholinesterase (AChE) precursors, Ace-orthologous AChE (AO-AChE) and Ace-paralogous AChE (AP-AChE), with 635 residues and 702 residues, respectively, were determined in Aedes albopictus by PCR-based techniques. The partial and whole cDNAs for AOAChE and AP-AChE, respectively, were also sequenced from a cultured cell line of mosquito, NIAS-AeAl-2, derived from Ae. albopictus neonatal larvae. Comparing the sequences of the respective AChEs between cultured cells and mosquito whole body extracts, many nucleotide polymorphisms were found in both AChE cDNAs but only one amino acid substitution. The expression level of AChE genes in the cultured cells was low, 1/2 and 1/7 that of the mosquito body for AO-AChE and AP-AChE, respectively. The expression ratio of AO-AChE/AP-AChE was 1/2 in the cultured cells. AP-AChE genes was more highly expressed than AO-AChE genes in both cultured cells and the mosquito body. In an enzyme assay, the activity of AChE per protein in the cultured cells was 1/8 that of the mosquito body. The function of AChE in cultured cells is discussed based on the present and previous papers.

RNAi of ace1 and ace2 in Blattella germanica reveals their differential contribution to acetylcholinesterase activity and sensitivity to insecticides

“…The functional sense of these two AChEs is still unclear. ace1-type AChE appears to encode major AChE responsible for the physiological hydrolysis of ACh in non-Cyclorrhapha insects as judged by its much higher transcription level compared to ace2 in Plutella xylostella (Baek et al, 2005), Helicoverpa assulta and Aedes albopictus (Mizuno et al, 2006). Other evidences for the predominant role of ace1 have been reported, such as the AChE activity curves in the presence of inhibitors (Bourguet et al, 1996;Huchard et al, 2006).…”

Functional study of acetylcholinesterase genes in Bombyx mori ovary cells using RNA interference

“…Silkworm AChE is encoded by two ace genes ( ace1 and ace2 ). The transcription level of ace1 is usually higher than that of ace2 in silkworm and other insects, such as Plutella xylostella (L.), Helicoverpa assulta (Guenée), and Aedes albopictus (Skuse) (Baek et al., 2005; Lee et al., 2006; Mizuno et al., 2006). Despite its lower expression level in various silkworm tissues, ace2 may still have important functions, as reported previously (Chen et al., 2009).…”

Biochemical properties of recombinant acetylcholinesterases with amino acid substitutions in the active site

“…Recent studies on AChE gene expression in some insect species indicate that AO-AChE gene expression is much lower than the AP-AChE gene in the insect body (Baek et al, 2005;Mizuno et al, 2006). Insensitivity appears to depend on a low level of expression of AO-AChE in the insect body as compared to AP-AChE.…”