House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE) activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi). Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA) pathway, which has been replaced by a novel small-interfering RNA (siRNA)-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution. Author summaryInvestigation of small RNA populations in dust mites revealed absence of the piwi-associated RNA (piRNA) pathway. Apart from several nematode and platyhelminths lineages, piRNAs are an essential component of animal genome surveillance, actively targeting and silencing transposable elements. In dust mites, expansion of Dicer produced small-interfering RNA (siRNA) biology compensates for loss of piRNAs. The dramatic difference we find in dust mites is likely a consequence of their evolutionary history, which is marked by descent from a parasite to the current free-living form. Our study highlights a correlation between perturbation of transposon surveillance and shifts in ecology.
The major storage protein within seeds of the Euphorbiaceae is the 11S crystalloid, which is only completely soluble in buffer or salt solutions if sodium dodecylsulphate or urea is present. Prior to this study, only the storage proteins of the castor bean had been characterized. The nonreduced crystalloid protein complex in all species tested has a molecular weight of 50 000 – 55 000, and in reduced form the proteins migrate on polyacrylamide gels as two distinct groups of polypeptides, one in the molecular weight range 20 000 – 25 000 and the other in the 29 000 – 35 000 range. In this respect the proteins have the general characteristics of those of castor bean, but only the proteins of Jatropha gossypifolia show striking similarities. Within any one genus, the storage proteins appear to be more or less identical (e.g., Manihot spp.) or show distinct differences (e.g., Euphorbia spp.). The soluble lectin proteins of J. gossypifolia have very similar haemagglutination properties to those of castor bean lectins, and the glycoproteins of both species separate similarly on polyacrylamide gels. Few other species contain glycoproteins or lectins that can cause agglutination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.