Characterisation of iron regulatory protein 1A and 1B in the blood-feeding copepod Lepeophtheirus salmonis

TitleCharacterisation of iron regulatory protein 1A and 1B in the blood-feeding copepod Lepeophtheirus salmonis
AuthorsTröße C, Kongshaug H, Dondrup M, Nilsen F
TypeJournal Article
Journal NameExperimental parasitology
CitationTröße C, Kongshaug H, Dondrup M, Nilsen F. Characterisation of iron regulatory protein 1A and 1B in the blood-feeding copepod Lepeophtheirus salmonis. Experimental parasitology. 2015 Jun 24.


During its parasitic life stages, the marine ectoparasitic copepod Lepeophtheirus salmonis ingests large amounts of host blood, which contains high amounts of iron. Iron is an essential micronutrient, but also toxic in high dosages, and blood-feeding parasites like the salmon louse must thus possess an efficient system to handle the excess iron. Iron regulatory protein 1 and 2 (IRP1 and IRP2) are known to play crucial roles in this process, by regulating several proteins involved in iron transport and storage, depending on the cellular iron concentration. To gain knowledge about the regulation of the iron metabolism in salmon lice, two IRP homologues (LsIRP1A and LsIRP1B) were identified by sequence and predicted structure similarity to known IRPs in other species. In situ hybridisation revealed that LsIRP1A and LsIRP1B mRNAs were expressed in the ovaries, oviducts and vitellogenic oocytes of adult females. Transcription levels of LsIRP1A and LsIRP1B mRNAs did not differ significantly between the different developmental stages of the salmon louse. Adults in the absence of blood as a feed source had decreased levels of LsIRP1A, but not LsIRP1B mRNA. RNA binding experiments indicated the presence of functioning IRP in salmon lice. In order to explore the biological functions of LsIRP1A and LsIRP1B, the mRNAs of both proteins were knocked down by RNA interference (RNAi) in preadult females. The knockdown was confirmed by qRT-PCR. LsIRP1B knockdown lice produced less offspring than control lice due to slightly shorter egg strings and had decreased levels of transcripts involved in egg development. Knockdown of both LsIRP1A and LsIRP1B caused increased expression of a salmon louse Ferritin (LsFer). These results confirm that salmon lice have two IRP1 homologues, LsIRP1A and LsIRP1B, and might suggest a function in cellular iron regulation in the reproductive organs and eggs.

Author Details
Additional information about authors:
1Christiane Tröße
2Heidi Kongshaug
3Michael Dondrup
4Frank Nilsen
Additional details for this publication include:
Property NameValue
Publication ModelPrint-Electronic
Publication Date2015 Jun 24
Journal AbbreviationExp. Parasitol.
CopyrightCopyright © 2015. Published by Elsevier Inc.
Language AbbrENG
Publication TypeJournal Article
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PMID: PMID:26115940