ABC transporters in the Daphnia pulex genome: Implications for ecotoxicology and drug resistance in crustacean parasites

Sturm, Armin; George, Stephen S.; Dean, Michael; Cunningham, Phil; Treuner-Freeman, Anke

doi:10.1016/j.cbpa.2009.04.154

Cited by 3 publications

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“…A total of 64 ATP-binding cassette (ABC) proteins were identified in the D. pulex ABC-transporter gene family, and many of them were assigned to drug efflux transporters homologous to other species [ 31 ]. It has been suggested that the increased expression of ABC transporters constitutes an adaptive mechanism enabling organisms to be resistant to drugs and toxicants [ 32 ]. Here, in D. magna , many transporter genes were down-regulated in response to dietary microcystins, which suggests that these transporters are involved in microcystin up-take rather than in excretion.…”

Section: Resultsmentioning

confidence: 99%

Deciphering the genetic basis of microcystin tolerance

et al. 2014

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BackgroundCyanobacteria constitute a serious threat to freshwater ecosystems by producing toxic secondary metabolites, e.g. microcystins. These microcystins have been shown to harm livestock, pets and humans and to affect ecosystem service and functioning. Cyanobacterial blooms are increasing worldwide in intensity and frequency due to eutrophication and global warming. However, Daphnia, the main grazer of planktonic algae and cyanobacteria, has been shown to be able to suppress bloom-forming cyanobacteria and to adapt to cyanobacteria that produce microcystins. Since Daphnia’s genome was published only recently, it is now possible to elucidate the underlying molecular mechanisms of microcystin tolerance of Daphnia.ResultsDaphnia magna was fed with either a cyanobacterial strain that produces microcystins or its genetically engineered microcystin knock-out mutant. Thus, it was possible to distinguish between effects due to the ingestion of cyanobacteria and effects caused specifically by microcystins. By using RNAseq the differentially expressed genes between the different treatments were analyzed and affected KOG-categories were calculated. Here we show that the expression of transporter genes in Daphnia was regulated as a specific response to microcystins. Subsequent qPCR and dietary supplementation with pure microcystin confirmed that the regulation of transporter gene expression was correlated with the tolerance of several Daphnia clones.ConclusionsHere, we were able to identify new candidate genes that specifically respond to microcystins by separating cyanobacterial effects from microcystin effects. The involvement of these candidate genes in tolerance to microcystins was validated by correlating the difference in transporter gene expression with clonal tolerance. Thus, the prevention of microcystin uptake most probably constitutes a key mechanism in the development of tolerance and adaptation of Daphnia. With the availability of clear candidate genes, future investigations examining the process of local adaptation of Daphnia populations to microcystins are now possible.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-776) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Deciphering the genetic basis of microcystin tolerance

et al. 2014

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“…TMDs typically contain several transmembrane helices, and NBDs have several conserved motifs: Walker A motif, Q loop, Signature motif and Walker B motif 1 4 . According to domain organizations and primary sequence homology, eukaryotic ABC transporters have been classified into seven families, from ABCA to ABCG 5 6 7 8 9 10 11 12 . Members of the seven ABC transporter families are widely distributed in eukaryotes.…”

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“…Most previous work on ABC transporter genes focused on either function 18 or phylogeny 7 10 11 13 14 19 . Two large-scale analyses of ABC transporters were conducted across multiple kingdoms.…”

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Tracing the structural evolution of eukaryotic ATP binding cassette transporter superfamily

Xiong

Feng

Yuan

et al. 2015

Sci Rep

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The ATP binding cassette (ABC) transporters superfamily is one of the largest classes of membrane proteins. The core of the ABC transporter protein is composed of transmembrane domains (TMDs) and nucleotide binding domains (NBD). Eukaryotes ABC transporters are classified into seven main families (ABCA to ABCG) based on sequence similarity and domain organizations. With different domain number and domain organizations, eukaryote ABC transporters show diverse structures: the single structure (NBD or TMD), the ABC2 structure (NBD-NBD), the half structure (TMD-NBD or NBD-TMD) and the full structure (TMD-NBD-TMD-NBD or NBD-TMD-NBD-TMD). However, studies on how various ABC transporter gene structures evolved is still absent. Therefore, in this study, we comprehensively investigated the structural evolution of eukaryotic ABC transporters. The seven eukaryote ABC transporter families (A to G) fell into three groups: A&G group, B,C&D group and E&F group. There were at least four times the number of NBD and TMD fusion events in the origin of the half structure transporter. Two fusion modes were found in the full and ABC2 structure origination. Based on these findings, we present a putative structural evolutionary path of eukaryote ABC transporters that will increase our understanding on their origin, divergence and function.

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Dietary exposure of Daphnia to microcystins: No in vivo relevance of biotransformation

Sadler¹,

Elert²

2014

Aquatic Toxicology

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ABC transporters in the Daphnia pulex genome: Implications for ecotoxicology and drug resistance in crustacean parasites

Cited by 3 publications

References 0 publications

Deciphering the genetic basis of microcystin tolerance

Deciphering the genetic basis of microcystin tolerance

Tracing the structural evolution of eukaryotic ATP binding cassette transporter superfamily

Dietary exposure of Daphnia to microcystins: No in vivo relevance of biotransformation

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