Identification and functional analysis of an iron‐binding protein, ferritin heavy chain subunit, from the swallowtail butterfly, Papilio xuthus

Abstract

Ferritin, which is ubiquitous among all living organisms, plays a crucial role in maintaining iron homeostasis, immune response, and detoxification. In the present research, we identified an iron-binding protein, ferritin heavy chain subunit, from Papilio xuthus and named PxFerHCH. The complete complementary DNA of PxFerHCH was 1,252 bp encoding a sequence of 211 amino acids, which includes an iron-responsive element. Phylogenetic analysis showed that PxFerHCH is clustered with Manduca sexta and Galleria mellonella ferritin heavy chain subunits. Expression levels of PxFerHCH in various tissues were analyzed by reverse transcription quantitative polymerase chain reaction, and the results exhibited that PxFerHCH was expressed in all tissues with the highest expression in the fat body. The relative expression level of PxFerHCH in response to bacterial (Escherichia coli and Staphylococcus aureus) challenges sharply increased by about 12 hr postinfection (hpi) and then decreased at 24 hpi. In addition, the iron-binding capacity and antioxidation activity of recombinant PxFerHCH protein were also investigated. These results reveal that PxFerHCH might play an important role in defense against bacterial infection.

RNAi‐mediated silencing of ferritin genes in the brown planthopper Nilaparvata lugens affects survival, growth and female fecundity

“…found that the injection of recombinant ferritin helped inhibit bacterial growth in the silkworm Bombyx mori by limiting the iron level in the hemolymph. Similar results have indicated that ferritin expression is upregulated in response to pathogen challenges in the swallowtail butterfly Papilio xuthus (Lepidoptera), 22 the beetle Tribolium castaneum (Coleoptera), 23 the bumblebee Bombus ignitus (Hymenoptera), 24 the horseshoe crab Limulus (Merostomata) 25 and the ark shell Scapharca broughtonii (Lamellibranchia) 26 . Taken together, these findings indicate that ferritin can function as an acute antibiotic protein by storing iron in host cells to inhibit pathogen growth.…”

“…It is extensively believed that ferritin is ubiquitously distributed among living organisms and consists of two subunits, Fer1HCH and Fer2LCH, in insects. In this study, NlFer1 and NlFer2 from BPH were found to possess ferritin domains and signal peptides similar to those from other species, 15,22,[45][46][47][48][49] suggesting that they might have similar functions in iron homeostasis. 19,46 However, the tissue expression patterns of ferritin vary slightly among different species.…”

“…In noninsect species, for example, the highest expression of ferritin in the ark shell Scapharca broughtonii was detected in feet and gill. 26 According to previous studies, ferritins are generally highly expressed in fat bodies and guts in insects, 15,22,24,[51][52][53] which is closely related to iron absorption and iron transportation. The results of this study showed that NlFer1 and NlFer2 were both highly expressed in guts, indicating that their functions in BPH might be related to feeding and nutrient digestion.…”

“…[13][14][15][19][20][21]27 Similarly, in this study, NlFer1 and NlFer2 were both expressed mostly in the gut throughout the whole lifespan, and high lethality was caused in dsNlFer1/NlFer2-treated BPH nymphs. Interestingly, in some insect species, silencing Fer1HCH showed more severe effects than silencing Fer2LCH, 17,19,21,22,28,30,46,[54][55][56] but we found that dsNlFer1-and dsNlFer2-treated BPHs showed similar phenotypes and survival rates. RNAi efficiency and sensitivity vary among different genes.…”

The molecular and functional characterization of ferritins in the hard tick Hyalomma rufipes

“…The relative expression level of ferritin heavy chain subunit from Papilio xuthus sharply increased in response to bacterial (Escherichia coli and Staphylococcus aureus) challenge [27]. The infection rate and proliferation rate of white spot syndrome virus in ferritin-silenced Procambarus clarkii were significantly increased [28].…”