Gene annotation of nuclear receptor superfamily genes in the kissing bug Rhodnius prolixus and the effects of 20‐hydroxyecdysone on lipid metabolism

Abstract

The hormone 20‐hydroxyecdysone is fundamental for regulating moulting and metamorphosis in immature insects, and it plays a role in physiological regulation in adult insects. This hormone acts by binding and activating a receptor, the ecdysone receptor, which is part of the nuclear receptor gene superfamily. Here, we analyse the genome of the kissing bug Rhodnius prolixus to annotate the nuclear receptor superfamily genes. The R. prolixus genome displays a possible duplication of the HNF4 gene. All the analysed insect organs express most nuclear receptor genes as shown by RT‐PCR. The quantitative PCR analysis showed that the RpEcR and RpUSP genes are highly expressed in the testis, while the RpHNF4‐1 and RpHNF4‐2 genes are more active in the fat body and ovaries and in the anterior midgut, respectively. Feeding does not induce detectable changes in the expression of these genes in the fat body. However, the expression of the RpHNF4‐2 gene is always higher than that of RpHNF4‐1. Treating adult females with 20‐hydroxyecdysone increased the amount of triacylglycerol stored in the fat bodies by increasing their lipogenic capacity. These results indicate that 20‐hydroxyecdysone acts on the lipid metabolism of adult insects, although the underlying mechanism is not clear.

Diet supplementation with egg yolk powder fattens the beetle Tribolium castaneum

“…The ACLY activity was measured as described elsewhere (Nascimento et al, 2021). Briefly, the insects were homogenized in 0.1 mM Tris-HCl buffer, pH 7.2.…”

Knockdown of ecdysone receptor in male desert locusts affects relative weight of accessory glands and mating behavior

“…However, to do so, more data on the MAG secretions and the activities of different gland types in S. gregaria would be needed. Furthermore, EcR has been shown to play a regulatory role in fat body of various insects where it affects lipid metabolism (Kamoshida et al, 2012;Lu et al, 2018;Nascimento et al, 2021;Wang et al, 2017). However, the only report on the role of ecdysteroids in the fat body of adult males comes from D. melanogaster, where a mild inactivation of EcR specifically in the fat body increases lifespan (Tricoire et al, 2009).…”

A critical role for ecdysone response genes in regulating egg production in adult female Rhodnius prolixus

“…Currently, only one ortholog for each of the ecdysone response genes, E75 , HR3 , HR4 , and FTZ - F1 , has been reported to be present in the R . prolixus genome [ 38 ]. It must be born in mind that this is not the case in other insects.…”

“…melanogaster , which are produced by alternative transcription and splicing [ 25 , 42 ], some insect species have only documented one transcript of FTZ - F1 [ 43 , 44 ], including R . prolixus [ 38 ].…”

“…Ecdysteroid titer peaks in the hemolymph five days PBM in both mated and virgin females, and ovariectomy reduces the ecdysteroid titer. Thus, ecdysteroid is synthesized and released from the ovaries [34,36,37]. Recently we identified the Halloween genes and the ecdysone receptor in the ovary of R. prolixus [37].…”