The structure of the juvenile hormone binding protein gene from Galleria mellonella

CRISPR/Cas9-Mediated Knockout of the PxJHBP Gene Resulted in Increased Susceptibility to Bt Cry1Ac Protoxin and Reduced Lifespan and Spawning Rates in Plutella xylostella

Juvenile hormone binding protein (JHBP) is a key regulator of JH signaling, and crosstalk between JH and 20-hydroxyecdysone (20E) can activate and fine-tune the mitogen-activated protein kinase cascade, leading to resistance to insecticidal proteins from Bacillis thuringiensis (Bt). However, the involvement of JHBP in the Bt Cry1Ac resistance of Plutella xylostella remains unclear. Here, we cloned a full-length cDNA encoding JHBP, and quantitative real-time PCR (qPCR) analysis showed that the expression of the PxJHBP gene in the midgut of the Cry1Ac-susceptible strain was significantly higher than that of the Cry1Ac-resistant strain. Furthermore, CRISPR/Cas9-mediated knockout of the PxJHBP gene significantly increased Cry1Ac susceptibility, resulting in a significantly shorter lifespan and reduced fertility. These results demonstrate that PxJHBP plays a critical role in the resistance to Cry1Ac protoxin and in the regulation of physiological metabolic processes associated with reproduction in adult females, providing valuable insights to improve management strategies of P. xylostella.

Juvenile hormone mimics with phenyl ether and amide functionality to be insect growth regulators (IGRs): synthesis, characterization, computational and biological study

A series of substituted phenyl ethers derivatives as juvenile hormone (JH) mimics (V₁-V₈) have been synthesized. Substituted phenoxyacetic acid and amino acid ethyl ester hydrochloride were prepared using NaOH, SOCl₂. DCC method has been used for amide linkage. The structure of prepared compounds has been confirmed by Fourier Transform Infra-Red (FT-IR), Electrospray ionization-Mass spectrometry (ESI-MS), Proton and Carbon-13 nuclear magnetic resonance (¹H-NMR, ¹³C-NMR) spectroscopic techniques. Biological efficacy of synthesized analogs has been carried out under laboratory conditions. Galleria mellonella (honey bee pest) has been chosen as testing insect. Juvenile hormone (JH) activity of synthesized compounds has been tested at different concentrations and compared with the standard juvenile hormone analogs (JHAs) pyriproxyfen (M₁) and fenoxycarb (M₂) against the fifth larval instar of G. mellonella. Compound ethyl 2-[2-(4-methylphenoxy)aminoacetyl]-3-phenyl-propanoate (V₆) exhibited better activity among all the synthesized compounds (V₁-V₈) with LC₅₀ and LC₉₀ values of 0.11 mg/mL and 0.56 mg/mL respectively. Compounds showed insect growth regulating (IGR) activity at lower concentrations. In silico screening of all synthesized compounds with the W-cavity of juvenile hormone-binding protein (JHBP) of insect G. mellonella has been carried out. Chemical reactivity of synthesized series has been studied using DFT/B3LYP/6-311 + G(d,2p) method. Non-toxic behavior of molecules has also been observed from ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) study using discovery studio client 3.0.Communicated by Ramaswamy H. Sarma.

Dissecting the Role of Juvenile Hormone Binding Protein in Response to Hormone and Starvation in the Cotton Bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Juvenile hormone (JH) regulates many physiological processes in insect development, diapause, and reproduction. Juvenile hormone binding protein (JHBP), the carrier partner protein of JH, is essential for the balance of JH titer to regulate the metamorphosis and development of insect. In this study, two JHBP genes were identified from Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), namely HaJHBP1 and HaJHBP2. The tissue and temporal expression pattern revealed that both HaJHBP1 and HaJHBP2 were dominantly expressed in larval fat body, and their high transcription stages were detected in fourth and fifth instars. The ingestion of methoprene, a JH analogue, significantly induced the expression of HaJHBP1 and HaJHBP2. However, both HaJHBP1 and HaJHBP2 mRNA levels were significantly downregulated after treated with a JH antagonist, precocene. When subject to starvation, larvae showed a marked suppressive effect in the expression of HaJHBP1 and HaJHBP2. These results indicate that JHBP plays a part in the JH-regulated metabolism, growth, or development in reaction to different nutritional conditions.

Genome-wide identification and analysis of JHBP-domain family members in the silkworm Bombyx mori

Juvenile hormone (JH) regulates the insect growth and development. JH appears in the hemolymph bound by a specific glycoprotein, juvenile hormone-binding protein (JHBP), which serves as a carrier to release the hormone to target tissues and cells. However, JHBP family candidates, expression patterns, and functional implications are still unclear. In this study, we identified 41 genes-containing conserved JHBP domains distributed across eight chromosomes of the silkworm Bombyx mori. A phylogenetic tree showed that the silkworm JHBP (BmJHBP) genes could be classified into two major branches and four subfamilies. Microarray data revealed that BmJHBP genes exhibit various expression patterns and are expressed in different tissues, periods, and sexes. The expression of BmJHBP genes was generally higher in the head, integument, midgut, fat body, testis, and ovary than in the anterior of the silk gland (ASG), median of the silk gland (MSG), posterior of the silk gland (PSG), hemocyte, and Malpighian tubule. BmJHBPd2, in particular, was investigated by Western Blotting, and immunofluorescent assay and was found to be highly expressed in the PSG cytoplasm on day 3 of the fifth instar, coinciding with silk production. Taken together, our findings will be useful in improving understanding the complexity of the JHBP family, and will lay the foundation of explaining functional characterization for further research.

Different pattern of Galleria mellonella jhbp gene expression in high five and Sf9 cells

Juvenile hormone binding protein (JHBP) is the key element of the system that transmits hormone signals to target tissues. Recently, we found that the core promoter of the jhbp gene is strongly under the control of the TATA box and the transcription start site. In this report, we have shown that the jhbp promoter contains distal regulatory elements whose functionality clearly depends on the particular cell environment and that the scope of research from one cell line is insufficient to generalize the conclusions of the analysis. Cf1/Usp (where Usp is ultraspiracle protein previously known as Cf1, chorion factor 1) elements suppressed transcription of the reporter gene in the High Five cell line but not in the Sf9 cell line. However, upstream from all three Cf1/Usp elements there is a DNA sequence, containing the Zeste element, which activates jhbp in both systems. We found that juvenile hormone strongly inhibited the activity of the jhbp promoter in the Sf9 cell line, whereas it did not have an effect in the High Five cell line. A second key hormone that controls insect development--20-hydroxyecdysone, was also found to suppress the transcription of jhbp. This is the first report describing how these two hormones affect jhbp gene expression in different cell lines.

Molecular characterization and gene expression of juvenile hormone binding protein in the bamboo borer, Omphisa fuscidentalis

Juvenile hormone (JH) plays an important role in many physiological processes in insect development, diapause and reproduction. An appropriate JH titer in hemolymph is essential for normal development in insects. Information concerning its carrier partner protein, juvenile hormone binding protein (JHBP), provides an alternative approach to understanding how JH regulates metamorphosis. In this study, we cloned and sequenced the Omphisa juvenile hormone binding protein (OfJHBP). The full-length OfJHBP cDNA sequence is comprised of 849 nucleotides with an open reading frame of 726bp encoding 242 amino acids. The molecular mass of the protein was estimated to be 26.94kDa. The deduced protein sequence of OfJHBP showed moderate homology with the lepidopteran, Heliothis virescens JHBP (52% amino acid identity) and lower homology with the Bombyx mori JHBP (45%) and the Manduca sexta JHBP (44%). The OfJHBP was expressed mainly in the fat body. OfJHBP transcripts in the fat body was moderately high during 3rd, 4th and 5th instars, then rapidly increased, reaching a peak during early diapause. The expression remained high in mid-diapause, then decreased in late-diapause until the pupal stage. Both juvenile hormone analog (JHA), methoprene, 20-hydroxyecdysone (20E) exhibited a similar stimulatory pattern in OfJHBP expression of diapausing larvae. OfJHBP mRNA levels gradually increased and showed a peak of gene expression on the penultimate, then declined to low levels in the pupal stage. For in vitro gene expression, both of JHA and 20E induced OfJHBP mRNA expression in fat body. Fat body maintenance in vitro in the presence of 0.1μg/50μl JHA induced OfJHBP mRNA expression to high levels within the first 30min whereas 0.1μg/50μl 20E induced gene expression at 120min. To study the synergistic effect of these two hormones, fat body was incubated in vitro with 0.1μg/50μl JHA or 0.1μg/50μl 20E or a combination of both hormone for 30min. Induction of OfJHBP expression by JHA and 20E was significantly greater than that of either hormone alone. These results should contribute to our understanding of how JHBP and JH regulate the termination of larval diapause in the bamboo borer.

Insect juvenile hormone binding protein shows ancestral fold present in human lipid-binding proteins

Low molecular weight juvenile hormone binding proteins (JHBPs) are specific carriers of juvenile hormone (JH) in the hemolymph of butterflies and moths. As hormonal signal transmitters, these proteins exert a profound effect on insect development. The crystal structure of JHBP from Galleria mellonella shows an unusual fold consisting of a long alpha-helix wrapped in a highly curved antiparallel beta-sheet. JHBP structurally resembles the folding pattern found in tandem repeats in some mammalian lipid-binding proteins, with similar organization of one cavity and a disulfide bond between the long helix and the beta-sheet. JHBP reveals, therefore, an archetypal fold used by nature for hydrophobic ligand binding. The JHBP molecule possesses two hydrophobic cavities. Several lines of experimental evidence conclusively indicate that JHBP binds JH in only one cavity, close to the N- and C-termini, and that this binding induces a structural change. The second cavity, located at the opposite end of the molecule, could bind another ligand.

Investigation of hormone activity in butterfly imaginal wing discs by protein expression pattern changes

In a proteomic approach using 2-DE, the changes in protein expression patterns in wing imaginal discs induced by hormone treatment have been studied. Here we show the response of butterfly imaginal wing disc tissue taken from late fifth instar larvae of the African-Mocker swallowtail Papilio dardanus (Lepidoptera) to the insect hormones 20-hydroxyecdysone (20-HE) and juvenile hormone (JH). The tissues were cultured in the presence of one hormone or a combination of both and their protein expression was compared to the pattern obtained from untreated wing discs. All the treatments resulted in changes in the expression pattern distinct from the uninduced control, indicating a distinct protein regulation induced by the hormones. The treatment with both of the hormones, which are known to have antagonistic physiological effects, did show a unique pattern, presumably the result, in part, of synergistic effects on protein expression mediated by the combined effects of both the hormones. The extent of the interaction between JH and 20-HE indicates a complex molecular regulation, far beyond a simple antagonistic effect.