Abstract
Among its other biological roles, acetylcholinesterase (AChE, EC 3.1.1.7), encoded by two ace in most insects, catalyses the breakdown of acetylcholine, thereby terminating synaptic transmission. ace1 encodes the synaptic enzyme and ace2 has other essential actions in many insect species, such as Chilo suppressalis and Plutella xylostella. The silkworm, Bombyx mori, has been domesticated for more than two thousand years and its aces have no history of pesticide exposure. Here, we investigated the functional differences between two ace genes, BmAce1 and BmAce2, in the silkworm. qPCR analysis indicated that BmAce1 is highly expressed in muscle and BmAce2 is more ubiquitously expressed among tissues and enriched in the head. Both genes were separately suppressed using chemically synthesized siRNAs. The mRNA abundance of the two ace genes was significantly reduced to about 13% – 75% of the control levels after siRNA injection. The AChE activities were decreased to 32% to 85% of control levels. Silencing BmAce2 resulted in about 26% mortality, faster and higher than the 20% in the siBmAce1-treated group. Silencing BmAce1 impacted motor control and development to a greater extent than silencing BmAce2, although both treatment groups suffered motor disability, slowed development and reduced cocoons. Both genes have essential, differing biological significance.
Highlights
Acetylcholinesterase (AChE, EC 3.1.1.7) hydrolyzes the neurotransmitter acetylcholine into acetate and choline with a very high catalytic activity of about 25,000 molecules per second
AChE1 is the major enzyme in insects, which is more abundant than AChE2
The AChE2 in B. mori and Apis mellifera is the major enzyme in synaptic transmission[20, 21]
Summary
Acetylcholinesterase (AChE, EC 3.1.1.7) hydrolyzes the neurotransmitter acetylcholine into acetate and choline with a very high catalytic activity of about 25,000 molecules per second. Separate gene silencing experiments with B. germanica indicate that Bgace[1] encodes the predominant AChE. We infer that while both genes are necessary, ace[1] predominates in some, but certainly not all insect species. AChE regulates cell-matrix interactions in bone[27] In nervous tissues, it influences neuroblastoma cell adhesion and neurite outgrowth[28]. Silencing larval H. armigera aces with dietary siRNAs led to high mortality, growth inhibition, malformation and drastically reduced fecundity, indicating to us the aces are multi-functional genes[32]. Silencing the larval aces in Chilo suppressalis and P. xylostella showed that Csace[1], Pxace[1] and Pxace[2] have non-typical functions in regulating larval growth and motor control[12, 34]. We present and discuss the outcomes of experiments designed to test our hypothesis
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
