The Proctolin Gene and Biological Effects of Proctolin in the Blood-Feeding Bug, Rhodnius prolixus

Abstract

We have reinvestigated the possible presence or absence of the pentapeptide proctolin in Rhodnius prolixus and report here the cloning of the proctolin cDNA. The transcript is expressed in the central nervous system (CNS) and some peripheral tissues. The proctolin prepropeptide encodes a single copy of proctolin along with a possible proctolin-precursor-associated peptide. We have biochemically identified proctolin in CNS extracts and shown its distribution using proctolin-like immunoreactivity. Immunostained processes are found on the salivary glands, female and male reproductive tissues, and heart and associated alary muscles. Proctolin-like immunoreactive bipolar neurons are found on the lateral margins of the common oviduct and bursa. Proctolin is biologically active on R. prolixus tissues, stimulating increases in contraction of anterior midgut and hindgut muscles, and increasing heartbeat frequency. Contrary to the previous suggestion that proctolin is absent from R. prolixus, proctolin is indeed present and biologically active in this medically important bug.

Identification of G protein coupled receptors for opsines and neurohormones in Rhodnius prolixus. Genomic and transcriptomic analysis

“…For neuropeptides, we used the specific sequences of R. prolixus described earlier as queries Orchard et al, 2011;Sterkel et al, 2012;Zandawala et al, 2010) and orthologues from B. mori, D. melanogaster and T. castaneum for molecules not reported in R. prolixus. For GPCRs we used the sequences predicted in this study (see 2.1) and previous reports (Paluzzi and O'Donnell, 2012;Paluzzi et al, 2014;Zandawala et al, 2013) as queries.…”

“…We performed database searches in R. prolixus nervous system and T. dimidiata, T. infestans and T. pallidipennis normalized transcriptomes using the sequences of R. prolixus neuropeptide precursor genes previously described as queries Orchard et al, 2011;Sterkel et al, 2012). Orthologous sequences 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 …”

More than two decades of research on insect neuropeptide GPCRs: an overview

“…It stimulates or potentiates muscle contraction, is cardio-acceleratory and acts as a neurohormone (Orchard et al, 1989; Lange, 2002; Clark et al, 2006; Lange and Orchard, 2006; Nässel and Winther, 2010). The Drosophila gene for the proctolin receptor was identified and cloned (Egerod et al, 2003b; Johnson et al, 2003a,b; Taylor et al, 2004; Orchard et al, 2011). When the receptor was stably expressed in CHO/Gα 16 cells, a dose-dependent response was measured for proctolin (Egerod et al, 2003b).…”

The female reproductive system of the kissing bug, Rhodnius prolixus: Arrangements of muscles, distribution and myoactivity of two endogenous FMRFamide-like peptides

“…The immunohistochemical protocol has been explained previously [26] with the following modifications. The tissues were incubated in rabbit anti-FMRFamide primary antiserum (1:1000 in phosphate buffered saline (PBS; 2.1 mM NaH 2 PO 4 , 8.3 mM Na 2 HPO 4 , 150 mM NaCl, pH 7.2) containing 0.4% Triton-X-100 and 2% normal goat serum (NGS)) for 48 h at 4 • C. Following the incubation in 1 • antiserum, the tissues were washed frequently for 6 h and then incubated in goat anti-rabbit antibody conjugated to Cy3 (1:600 in 10% NGS in PBS) overnight at 4 • C. Preparations were then washed repeatedly in PBS, run through a glycerol series and mounted on glass slides.…”

“…For example, CCAP exhibits an excitatory effect on oviduct contractions of Manduca sexta and L. migratoria [7,20]. Extensive research has been carried out regarding the excitatory effect of proctolin on L. migratoria oviducts [16] and proctolin has also been found to play a role in controlling reproductive tissues of R. prolixus [19,26]. In contrast, myoinhibiting peptides (MIPs) have been found to have an inhibitory effect on the peristaltic contractions of the oviducts in Schistocerca gregaria [34], as have some FMRFamide-like peptides (FLPs) such as SchistoFLRFamide [31].…”