Molecular cloning and characterization of the allatotropin precursor and receptor in the desert locust, Schistocerca gregaria

Abstract

Allatotropins (ATs) are pleiotropic neuropeptides initially isolated from the tobacco hornworm, Manduca sexta. In 2008, the first receptor for AT-like peptides (ATR) was characterized in Bombyx mori. Since then, ATRs have also been characterized in M. sexta, Tribolium castaneum, Aedes aegypti and Bombus terrestris. These receptors show sequence similarity to vertebrate orexin (ORX) receptors. When generating an EST-database of the desert locust (Schistocerca gregaria) central nervous system, we found cDNA sequences encoding the Schgr-AT precursor and a fragment of its putative receptor. This receptor cDNA has now been completed and functionally expressed in mammalian cell lines. Activation of this receptor, designated as Schgr-ATR, by Schgr-AT caused an increase in intracellular calcium ions, as well as cyclic AMP (cAMP), with an EC50 value in the nanomolar range. In addition, the transcript distribution of both the Schgr-AT precursor and Schgr-ATR was investigated by means of quantitative real-time PCR. Moreover, we found more evidence for the myotropic and allatostimulatory actions of Schgr-AT in the desert locust. These data are discussed and situated in a broader context by comparison with literature data on AT and ATR in insects.

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

“…mori , the current study revealed the feeding regulatory function of AT by modulating intestinal contraction, which is a function, distinctive from allatoregulatory roles [32, 44]. Consistently, it is possible in other insect species that AT can modulate feeding motivation by its pleiotropic physiological and developmental functions [45–47] including myoregulatory activities on the foregut [25, 26, 48], midgut [27, 49] and hindgut [50, 51].…”

There is no magic bullet: the importance of testing reference gene stability in RT-qPCR experiments across multiple closely related species

“…We show that SPPP-4 expression in the thorax tissue from crowded-reared individuals is higher compared to isolated-reared individuals, and SPPP-5 shows a similar but a non-significant trend, consistent with earlier studies in S. gregaria (Badisco et al, 2011;Breugelmans et al, 2008;Simonet et al, 2005). The other two target genes were allatotropin, a pleiotropic hormone that is best known as a stimulator of juvenile hormone (JH) production and a myostimulatory peptide (Kataoka et al, 1989;Lismont et al, 2015), and allatostatin, known to repress JH production in insects even though this function could not be confirmed in S. gregaria (Stay, Tobe & Bendena, 1995;Verlinden et al, 2009). We report that ast is significantly downregulated in crowded-reared locusts, and observed a similar but non-significant trend for at.…”

“…Other differences between both technique (e.g., RNA sequencing being more prone to PCR artefacts and positional bias) might play an additional role in the observed differences. An earlier study in S. gregaria reported no significant difference between isolated-reared and crowded-reared individuals for at (Lismont et al, 2015), even though the data were not shown. Together, our data might suggest differences in JH regulation between isolated-reared and crowded-reared locusts.…”

Caracterización genómico funcional de los neuropéptidos Allatotropina y Allatostatina-C y sus receptores en insectos vectores de la enfermedad de Chagas

“…Mediante los alineamientos múltiples, observamos que Rp-ATr y Rp-AST-Cr comparten un alto grado de similitud con los receptores de otros insectos pertenecientes a especies de holometábolos y hemimetábolos (Vuerinckx et al, 2011;Horodyski et al, 2011;Nouzova et al, 2012;Verlinden et al, 2013;Lismont et al, 2015).…”

“…El receptor de AT (ATr) ha sido caracterizado genómica y funcionalmente por su alto grado de similitud con el receptor de orexina de vertebrados, en diferentes especies de insectos como B. mori, T. castaneum, M. sexta, A. aegypti, B. terrestres, S. gregaria (Yamanaka et al, 2008;Vuerinckx et al, 2011;Horodyski et al, 2011;Nouzova et al, 2012;Verlinden et al, 2013;Lismont et al, 2015) y su presencia ha sido predicha también en R. prolixus (Alzugaray et al, 2013). La expresión del mRNA se ha confirmado en órganos reproductores, en el SNC y en el complejo CC-CA y sistema digestivo, todos ellos órganos blanco de la acción del péptido (Verlinden et al, 2015).…”