The cytochrome P450 (CYP) gene superfamily in Daphnia pulex. BMC Genomics 10:169

Clemson University, Biological Sciences, Institute of Environmental Toxicology, Pendleton, SC, USA.
BMC Genomics (Impact Factor: 3.99). 05/2009; 10(1):169. DOI: 10.1186/1471-2164-10-169
Source: PubMed


Cytochrome P450s (CYPs) in animals fall into two categories: those that synthesize or metabolize endogenous molecules and those that interact with exogenous chemicals from the diet or the environment. The latter form a critical component of detoxification systems.
Data mining and manual curation of the Daphnia pulex genome identified 75 functional CYP genes, and three CYP pseudogenes. These CYPs belong to 4 clans, 13 families, and 19 subfamilies. The CYP 2, 3, 4, and mitochondrial clans are the same four clans found in other sequenced protostome genomes. Comparison of the CYPs from D. pulex to the CYPs from insects, vertebrates and sea anemone (Nematostella vectensis) show that the CYP2 clan, and to a lesser degree, the CYP4 clan has expanded in Daphnia pulex, whereas the CYP3 clan has expanded in insects. However, the expansion of the Daphnia CYP2 clan is not as great as the expansion observed in deuterostomes and the nematode C. elegans. Mapping of CYP tandem repeat regions demonstrated the unusual expansion of the CYP370 family of the CYP2 clan. The CYP370s are similar to the CYP15s and CYP303s that occur as solo genes in insects, but the CYP370s constitute approximately 20% of all the CYP genes in Daphnia pulex. Lastly, our phylogenetic comparisons provide new insights into the potential origins of otherwise mysterious CYPs such as CYP46 and CYP19 (aromatase).
Overall, the cladoceran, D. pulex has a wide range of CYPs with the same clans as insects and nematodes, but with distinct changes in the size and composition of each clan.

Download full-text


Available from: David R Nelson, Oct 02, 2015
1 Follower
43 Reads
  • Source
    • "produce the Δ 4 -diketol that is the central precursor to the multiple derivative steroid products. The cytochrome P450 enzyme Phm (Kappler et al., 1988; Niwa et al., 2004; Warren et al., 2004) and three mitochondria cytochrome P450 enzymes, Dib, Sad and Shd, complete the hydroxylation reactions of the pathway (Feyereisen, 2006, 2011, 2012; Rewitz et al., 2007; Baldwin et al., 2009; Mykles, 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The ecdysteroid biosynthetic pathway involves sequential enzymatic hydroxylations by a group of enzymes collectively known as Halloween gene proteins. Complete sequences for three Halloween genes, spook (Vdspo), disembodied (Vddib) and shade (Vdshd), were identified in varroa mites and sequenced. Phylogenetic analyses of predicted amino acid sequences for Halloween orthologues showed that the acarine orthologues were distantly associated with insect and crustacean clades indicating that acarine genes had more ancestral characters. The lack of orthologues or pseudogenes for remaining genes suggests these pathway elements had not evolved in ancestral arthropods. Vdspo transcript levels were highest in gut tissues, while Vddib transcript levels were highest in ovary-lyrate organs. In contrast, Vdshd transcript levels were lower overall but present in both gut and ovary-lyrate organs. All three transcripts were present in eggs removed from gravid female mites. A brood cell invasion assay was developed for acquiring synchronously staged mites. Mites within 4 h of entering a brood cell had transcript levels of all three that were not significantly different from mites on adult bees. These analyses suggest that varroa mites may be capable of modifying 7-dehydro-cholesterol precursor and hydroxylations of other steroid precursors, but whether the mites directly produce ecdysteroid precursors and products remains undetermined.
    Insect Molecular Biology 06/2015; 24(3). DOI:10.1111/imb.12155 · 2.59 Impact Factor
  • Source
    • "The first insect CYP gene, CYP6A1, was cloned from an insecticide-resistant strain of housefly, Musca domestica [6]. Since then, lots of CYP genes were identified in various insects [1] [5] [10]. The sequencing of numerous insect genomes has revealed dynamic changes in the number and identity of CYP genes in different insects [5]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The Cytochrome P450 (CYP) superfamily is a large group of ancient proteins with enzymatic activities involved in various physiological processes. The rice striped stem borer, Chilo suppressalis, is an important insect pest in rice production. Here, we report the identification and characterization of 77 CYP genes from rice striped stem borer (SSB) through genome and transcriptome sequence analyses. All these CYP genes were confirmed by RT-PCR and direct sequencing. Twenty-eight CYP transcripts have full open reading frame (ORF) and four additional transcripts have a nearly full length coding region. The SSB CYP genes were classified into four clans, the mitochondrial, CYP2, CYP3, and CYP4. Phylogenetic analysis indicated that there was an apparent expansion of the CYP3 clan in insects. The CYP6AB subfamily of the CYP3 clan had nine members in SSB. Evolutionary analysis showed that this subfamily was expanded only in lepidopteran insects. In this study, we identified a new P450 subfamily, CYP321F, which is unique to SSB and located in the genome as tandem repeats. Our work provided a foundation for future studies on the functions and mechanism of P450s in the destructive rice pest.
    Biochemical and Biophysical Research Communications 12/2013; 443(2). DOI:10.1016/j.bbrc.2013.12.045 · 2.30 Impact Factor
  • Source
    • "Endocrine disrupting activities of triazole fungicides in invertebrates The critical question is if P450-catalyzed reactions play a role in the endocrine systems of invertebrates, and if triazole fungicides such as epoxiconazole could inhibit those enzymes. Molecular and biochemical evidence of P450 enzymes have been demonstrated in all larger phyla of invertebrates, including Cnidaria, Annelida, Mollusca, Arthropoda and Echinodermata (Baldwin et al., 2009; Lee, 1998; Rewitz et al., 2006a; Snyder, 2000). Comparable to vertebrates, the main functions of invertebrate P450 enzymes are either catabolism of lipophilic endogenous and exogenous substrates, or the biosynthesis of signaling molecules including steroids (Rewitz et al., 2006b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Conventional risk assessments for crop protection chemicals compare the potential for causing toxicity (hazard identification) to anticipated exposure. New regulatory approaches have been proposed that would exclude exposure assessment and just focus on hazard identification based on endocrine disruption. This review comprises a critical analysis of hazard, focusing on the relative sensitivity of endocrine and non-endocrine endpoints, using a class of crop protection chemicals, the azole fungicides. These were selected because they are widely used on important crops (e.g. grains) and thereby can contact target and non-target plants and enter the food chain of humans and wildlife. Inhibition of lanosterol 14α-demethylase (CYP51) mediates the antifungal effect. Inhibition of other CYPs, such as aromatase (CYP19), can lead to numerous toxicological effects, which are also evident from high dose human exposures to therapeutic azoles. Because of its widespread use and substantial database, epoxiconazole was selected as a representative azole fungicide. Our critical analysis concluded that anticipated human exposure to epoxiconazole would yield a margin of safety of at least three orders of magnitude for reproductive effects observed in laboratory rodent studies that are postulated to be endocrine-driven (i.e. fetal resorptions). The most sensitive ecological species is the aquatic plant Lemna (duckweed), for which the margin of safety is less protective than for human health. For humans and wildlife, endocrine disruption is not the most sensitive endpoint. It is concluded that conventional risk assessment, considering anticipated exposure levels, will be protective of both human and ecological health. Although the toxic mechanisms of other azole compounds may be similar, large differences in potency will require a case-by-case risk assessment.
    Critical Reviews in Toxicology 11/2013; 44(2). DOI:10.3109/10408444.2013.855163 · 5.10 Impact Factor
Show more