A DNA G-quadruplex/i-motif hybrid.

DNA can form many structures beyond the canonical Watson-Crick double helix. It is now clear that noncanonical structures are present in genomic DNA and have biological functions. G-rich G-quadruplexes and C-rich i-motifs are the most well-characterized noncanonical DNA motifs that have been detected in vivo with either proscribed or postulated biological roles. Because of their independent sequence requirements, these structures have largely been considered distinct types of quadruplexes. Here, we describe the crystal structure of the DNA oligonucleotide, d(CCAGGCTGCAA), that self-associates to form a quadruplex structure containing two central antiparallel G-tetrads and six i-motif C-C+ base pairs. Solution studies suggest a robust structural motif capable of assembling as a tetramer of individual strands or as a dimer when composed of tandem repeats. This hybrid structure highlights the growing structural diversity of DNA and suggests that biological systems may harbor many functionally important non-duplex structures.

A conserved RNA structural motif for organizing topology within picornaviral internal ribosome entry sites.

Picornaviral IRES elements are essential for initiating the cap-independent viral translation. However, three-dimensional structures of these elements remain elusive. Here, we report a 2.84-Å resolution crystal structure of hepatitis A virus IRES domain V (dV) in complex with a synthetic antibody fragment-a crystallization chaperone. The RNA adopts a three-way junction structure, topologically organized by an adenine-rich stem-loop motif. Despite no obvious sequence homology, the dV architecture shows a striking similarity to a circularly permuted form of encephalomyocarditis virus J-K domain, suggesting a conserved strategy for organizing the domain architecture. Recurrence of the motif led us to use homology modeling tools to compute a 3-dimensional structure of the corresponding domain of foot-and-mouth disease virus, revealing an analogous domain organizing motif. The topological conservation observed among these IRESs and other viral domains implicates a structured three-way junction as an architectural scaffold to pre-organize helical domains for recruiting the translation initiation machinery.

siRNA containing a unique 5-nucleotide motif acts as a quencher of IFI16-mediated innate immune response.

We previously reported that some small interfering RNA (siRNA) enhances DNA or DNA virus mediated-interferon (IFN)-λ1(a type III IFN) induction through the crosstalk between retinoic acid-inducible gene I (RIG-I) and interferon gamma-inducible protein 16 (IFI16) signalling pathway. Here we provide further evidence of a new role for siRNA. siRNA containing a 5-nucleotide (nt) motif sequence suppresses DNA-mediated not only type III IFNs, but also type I IFNs and inflammatory cytokines. We define that motif siRNA inhibits the induction when the motif is located at the 3' or 5'-terminus of siRNA. Using THP1-Lucia ISG cells with various DNA stimulants, we reveal that motif siRNA inhibits DNA or DNA virus but not RNA virus-mediated signalling. Motif siRNA specifically interrupts IFI16 but not cyclic GMP-AMP synthase (cGAS) binding to DNA and has 2.5-fold higher affinity to IFI16 than that of siRNA without the motif. We further confirm that motif siRNA potently suppresses HSV-1 virus-mediated IFNs and inflammatory cytokines, such as IFNL1, IFNB and TNFA, in human primary immature dendritic cells. Collectively, these findings may shed light on a novel function of siRNA with the unique 5-nt motif as a quencher of innate immunity and facilitate the development of potential therapeutics to regulate innate immune cascades.

Identification of evolutionarily conserved downstream core promoter elements required for the transcriptional regulation of Fushi tarazu target genes.

The regulation of transcription initiation is critical for developmental and cellular processes. RNA polymerase II (Pol II) is recruited by the basal transcription machinery to the core promoter where Pol II initiates transcription. The core promoter encompasses the region from -40 to +40 bp relative to the +1 transcription start site (TSS). Core promoters may contain one or more core promoter motifs that confer specific properties to the core promoter, such as the TATA box, initiator (Inr) and motifs that are located downstream of the TSS, namely, motif 10 element (MTE), the downstream core promoter element (DPE) and the Bridge, a bipartite core promoter element. We had previously shown that Caudal, an enhancer-binding homeodomain transcription factor and a key regulator of the Hox gene network, is a DPE-specific activator. Interestingly, pair-rule proteins have been implicated in enhancer-promoter communication at the engrailed locus. Fushi tarazu (Ftz) is an enhancer-binding homeodomain transcription factor encoded by the ftz pair-rule gene. Ftz works in concert with its co-factor, Ftz-F1, to activate transcription. Here, we examined whether Ftz and Ftz-F1 activate transcription with a preference for a specific core promoter motif. Our analysis revealed that similarly to Caudal, Ftz and Ftz-F1 activate the promoter containing a TATA box mutation to significantly higher levels than the promoter containing a DPE mutation, thus demonstrating a preference for the DPE motif. We further discovered that Ftz target genes are enriched for a combination of functional downstream core promoter elements that are conserved among Drosophila species. Thus, the unique combination (Inr, Bridge and DPE) of functional downstream core promoter elements within Ftz target genes highlights the complexity of transcriptional regulation via the core promoter in the transcription of different developmental gene regulatory networks.

Complex between a Multicrossover DNA Nanostructure, PX-DNA, and T7 Endonuclease I.

Paranemic crossover DNA (PX-DNA) is a four-stranded multicrossover structure that has been implicated in recombination-independent recognition of homology. Although existing evidence has suggested that PX is the DNA motif in homologous pairing (HP), this conclusion remains ambiguous. Further investigation is needed but will require development of new tools. Here, we report characterization of the complex between PX-DNA and T7 endonuclease I (T7endoI), a junction-resolving protein that could serve as the prototype of an anti-PX ligand (a critical prerequisite for the future development of such tools). Specifically, nuclease-inactive T7endoI was produced and its ability to bind to PX-DNA was analyzed using a gel retardation assay. The molar ratio of PX to T7endoI was determined using gel electrophoresis and confirmed by the Hill equation. Hydroxyl radical footprinting of T7endoI on PX-DNA is used to verify the positive interaction between PX and T7endoI and to provide insight into the binding region. Cleavage of PX-DNA by wild-type T7endoI produces DNA fragments, which were used to identify the interacting sites on PX for T7endoI and led to a computational model of their interaction. Altogether, this study has identified a stable complex of PX-DNA and T7endoI and lays the foundation for engineering an anti-PX ligand, which can potentially assist in the study of molecular mechanisms for HP at an advanced level.

Deconstructing internal ribosome entry site elements: an update of structural motifs and functional divergences.

Beyond the general cap-dependent translation initiation, eukaryotic organisms use alternative mechanisms to initiate protein synthesis. Internal ribosome entry site (IRES) elements are cis-acting RNA regions that promote internal initiation of translation using a cap-independent mechanism. However, their lack of primary sequence and secondary RNA structure conservation, as well as the diversity of host factor requirement to recruit the ribosomal subunits, suggest distinct types of IRES elements. In spite of this heterogeneity, conserved motifs preserve sequences impacting on RNA structure and RNA-protein interactions important for IRES-driven translation. This conservation brings the question of whether IRES elements could consist of basic building blocks, which upon evolutionary selection result in functional elements with different properties. Although RNA-binding proteins (RBPs) perform a crucial role in the assembly of ribonucleoprotein complexes, the versatility and plasticity of RNA molecules, together with their high flexibility and dynamism, determines formation of macromolecular complexes in response to different signals. These properties rely on the presence of short RNA motifs, which operate as modular entities, and suggest that decomposition of IRES elements in short modules could help to understand the different mechanisms driven by these regulatory elements. Here we will review evidence suggesting that model IRES elements consist of the combination of short modules, providing sites of interaction for ribosome subunits, eIFs and RBPs, with implications for definition of criteria to identify novel IRES-like elements genome wide.

A B-ARR-mediated cytokinin transcriptional network directs hormone cross-regulation and shoot development.

Cytokinin fulfills its diverse roles in planta through a series of transcriptional responses. We identify the in vivo DNA binding site profiles for three genetically redundant type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs): ARR1, ARR10, and ARR12. The expression and genome-wide DNA binding locations of the three B-ARRs extensively overlap. Constructing a primary cytokinin response transcriptional network reveals a recurring theme of widespread cross-regulation between the components of the cytokinin pathway and other plant hormone pathways. The B-ARRs are found to have similar DNA binding motifs, though sequences flanking the core motif were degenerate. Cytokinin treatments amalgamate the three different B-ARRs motifs to identical DNA binding signatures (AGATHY, H(a/t/c), Y(t/c)) which suggests cytokinin may regulate binding activity of B-ARR family members. Furthermore, we find that WUSCHEL, a key gene required for apical meristem maintenance, is a cytokinin-dependent B-ARR target gene, demonstrating the importance of the cytokinin transcription factor network in shoot development.

Atf3 links loss of epithelial polarity to defects in cell differentiation and cytoarchitecture.

Interplay between apicobasal cell polarity modules and the cytoskeleton is critical for differentiation and integrity of epithelia. However, this coordination is poorly understood at the level of gene regulation by transcription factors. Here, we establish the Drosophila activating transcription factor 3 (atf3) as a cell polarity response gene acting downstream of the membrane-associated Scribble polarity complex. Loss of the tumor suppressors Scribble or Dlg1 induces atf3 expression via aPKC but independent of Jun-N-terminal kinase (JNK) signaling. Strikingly, removal of Atf3 from Dlg1 deficient cells restores polarized cytoarchitecture, levels and distribution of endosomal trafficking machinery, and differentiation. Conversely, excess Atf3 alters microtubule network, vesicular trafficking and the partition of polarity proteins along the apicobasal axis. Genomic and genetic approaches implicate Atf3 as a regulator of cytoskeleton organization and function, and identify Lamin C as one of its bona fide target genes. By affecting structural features and cell morphology, Atf3 functions in a manner distinct from other transcription factors operating downstream of disrupted cell polarity.

Non-canonical Escherichia coli transcripts lacking a Shine-Dalgarno motif have very different translational efficiencies and do not form a coherent group.

Translation initiation in 50-70 % of transcripts in Escherichia coli requires base pairing between the Shine-Dalgarno (SD) motif in the mRNA and the anti-SD motif at the 3' end of the 16S rRNA. However, 30-50 % of E. coli transcripts are non-canonical and are not preceded by an SD motif. The 5' ends of 44 E. coli transcripts were determined, all of which contained a 5'-UTR (no leaderless transcripts), but only a minority contained an SD motif. The 5'-UTR lengths were compared with those listed in RegulonDB and reported in previous publications, and the identities and differences were obtained in all possible combinations. We aimed to quantify the translational efficiencies of non-canonical 5'-UTRs using GusA reporter gene assays and Northern blot analyses. Ten non-canonical 5'-UTRs and two control 5'-UTRs with an SD motif were cloned upstream of the gusA gene. The translational efficiencies were quantified under five different conditions (different growth rates via two different temperatures and two different carbon sources, and heat shock). The translational efficiencies of the non-canonical 5'-UTRs varied widely, from 5 to 384 % of the positive control. In addition, the non-canonical transcripts did not exhibit a common regulatory pattern with changing environmental parameters. No correlation could be observed between the translational efficiencies of the non-canonical 5'-UTRs and their lengths, sequences, GC content, or predicted secondary structures. The introduction of an SD motif enhanced the translational efficiency of a poorly translated non-canonical transcript, while the efficiency of a well-translated non-canonical transcript remained unchanged. Taken together, the mechanisms of translation initiation at non-canonical transcripts in E. coli still need to be elucidated.

Recognition of the long range enhancer-promoter interactions by further adding DNA structure properties and transcription factor binding motifs in human cell lines.

The enhancer-promoter interactions (EPIs) with strong tissue-specificity play an important role in cis-regulatory mechanism of human cell lines. However, it still remains a challenging work to predict these interactions so far. Due to that these interactions are regulated by the cooperativeness of diverse functional genomic signatures, DNA spatial structure and DNA sequence elements. In this paper, by adding DNA structure properties and transcription factor binding motifs, we presented an improved computational method to predict EPIs in human cell lines. In comparison with the results of other group on the same datasets, our best accuracies by cross-validation test were about 15%-24% higher in the same cell lines, and the accuracies by independent test were about 11%-15% higher in new cell lines. Meanwhile, we found that transcription factor binding motifs and DNA structure properties have important information that would largely determine long range EPIs prediction. From the distribution comparisons, we also found their distinct differences between interacting and non-interacting sets in each cell line. Then, the correlation analysis and network models for relationships among top-ranked functional genomic signatures indicated that diverse genomic signatures would cooperatively establish a complex regulatory network to facilitate long range EPIs. The experimental results provided additional insights about the roles of DNA intrinsic properties and functional genomic signatures in EPIs prediction.

Comparative analysis of alternative polyadenylation in S. cerevisiae and S. pombe.

Alternative polyadenylation (APA) is a widespread mechanism that generates mRNA isoforms with distinct properties. Here we have systematically mapped and compared cleavage and polyadenylation sites (PASs) in two yeast species, S. cerevisiae and S. pombe Although >80% of the mRNA genes in each species were found to display APA, S. pombe showed greater 3' UTR size differences among APA isoforms than did S. cerevisiae PASs in different locations of gene are surrounded with distinct sequences in both species and are often associated with motifs involved in the Nrd1-Nab3-Sen1 termination pathway. In S. pombe, strong motifs surrounding distal PASs lead to higher abundances of long 3' UTR isoforms than short ones, a feature that is opposite in S. cerevisiae Differences in PAS placement between convergent genes lead to starkly different antisense transcript landscapes between budding and fission yeasts. In both species, short 3' UTR isoforms are more likely to be expressed when cells are growing in nutrient-rich media, although different gene groups are affected in each species. Significantly, 3' UTR shortening in S. pombe coordinates with up-regulation of expression for genes involved in translation during cell proliferation. Using S. pombe strains deficient for Pcf11 or Pab2, we show that reduced expression of 3'-end processing factors lengthens 3' UTR, with Pcf11 having a more potent effect than Pab2. Taken together, our data indicate that APA mechanisms in S. pombe and S. cerevisiae are largely different: S. pombe has many of the APA features of higher species, and Pab2 in S. pombe has a different role in APA regulation than its mammalian homolog, PABPN1.

Effect on gene expression of three allelic variants in GATA motifs of ABO, RHD, and RHCE regulatory elements.

BACKGROUND: Only a few genetic variants have been reported in regulatory elements of blood group genes. Most of them affect GATA motifs, binding sites for the GATA-1 transcription factor. STUDY DESIGN AND METHODS: Samples from two patients and one donor with unusual or discrepant serology for ABO, RhD, and RhCE antigens were analyzed by DNA sequencing. Analyzed regions included the coding sequence and portions of regulatory elements. The effect of some variants on gene expression was evaluated in reporter gene assays. RESULTS: Three new alleles were identified. Their key variants are located in the ABO Intron 1 enhancer, the RHD proximal promoter, and the RHCE proximal promoter. IVS1 + 5859A was found in an African American patient with a group O forward type and a group B reverse type. 5'UTR-115C was the only RHD variant sequence found in a mixed-race black and Caucasian prenatal patient showing mixed-field agglutination with anti-D. 5'UTR-83T was found in several black donors and patients in the context of the genetically related RHCE*ceBI and RHCE*ceSM alleles. Reporter assays of promoter constructs including 5'UTR-115C or 5'UTR-83T showed a significant reduction in RH gene expression. CONCLUSION: Three new alleles in the ABO, RHD, and RHCE genes consist of single-nucleotide changes within GATA motifs, emphasizing the key role of GATA transcription factors in the expression of blood group genes.

LEC1 sequentially regulates the transcription of genes involved in diverse developmental processes during seed development.

LEAFY COTYLEDON1 (LEC1), an atypical subunit of the nuclear transcription factor Y (NF-Y) CCAAT-binding transcription factor, is a central regulator that controls many aspects of seed development including the maturation phase during which seeds accumulate storage macromolecules and embryos acquire the ability to withstand desiccation. To define the gene networks and developmental processes controlled by LEC1, genes regulated directly by and downstream of LEC1 were identified. We compared the mRNA profiles of wild-type and lec1-null mutant seeds at several stages of development to define genes that are down-regulated or up-regulated by the lec1 mutation. We used ChIP and differential gene-expression analyses in Arabidopsis seedlings overexpressing LEC1 and in developing Arabidopsis and soybean seeds to identify globally the target genes that are transcriptionally regulated by LEC1 in planta Collectively, our results show that LEC1 controls distinct gene sets at different developmental stages, including those that mediate the temporal transition between photosynthesis and chloroplast biogenesis early in seed development and seed maturation late in development. Analyses of enriched DNA sequence motifs that may act as cis-regulatory elements in the promoters of LEC1 target genes suggest that LEC1 may interact with other transcription factors to regulate distinct gene sets at different stages of seed development. Moreover, our results demonstrate strong conservation in the developmental processes and gene networks regulated by LEC1 in two dicotyledonous plants that diverged ∼92 Mya.

Recurring RNA structural motifs underlie the mechanics of L1 stalk movement.

The L1 stalk of the large ribosomal subunit undergoes large-scale movements coupled to the translocation of deacylated tRNA during protein synthesis. We use quantitative comparative structural analysis to localize the origins of L1 stalk movement and to understand its dynamic interactions with tRNA and other structural elements of the ribosome. Besides its stacking interactions with the tRNA elbow, stalk movement is directly linked to intersubunit rotation, rotation of the 30S head domain and contact of the acceptor arm of deacylated tRNA with helix 68 of 23S rRNA. Movement originates from pivoting at stacked non-canonical base pairs in a Family A three-way junction and bending in an internal G-U-rich zone. Use of these same motifs as hinge points to enable such dynamic events as rotation of the 30S subunit head domain and in flexing of the anticodon arm of tRNA suggests that they represent general strategies for movement of functional RNAs.

Sap1 is a replication-initiation factor essential for the assembly of pre-replicative complex in the fission yeast Schizosaccharomyces pombe.

A central step in the initiation of chromosomal DNA replication in eukaryotes is the assembly of pre-replicative complex (pre-RC) at late M and early G1 phase of the cell cycles. Since 1973, four proteins or protein complexes, including cell division control protein 6 (Cdc6)/Cdc18, minichromosome maintenance protein complex, origin recognition complex (ORC), and Cdt1, are known components of the pre-RC. Previously, we reported that a non-ORC protein binds to the essential element Δ9 of the Schizosaccharomyces pombe DNA-replication origin ARS3001. In this study, we identified that the non-ORC protein is Sap1. Like ORC, Sap1 binds to DNA origins during cell growth cycles. But unlike ORC, which binds to asymmetric AT-rich sequences through its nine AT-hook motifs, Sap1 preferentially binds to a DNA sequence of 5'-(A/T) n (C/G)(A/T)9-10(G/C)(A/T) n -3' (n ≥ 1). We also found that Sap1 and ORC physically interact. We further demonstrated that Sap1 is required for the assembly of the pre-RC because of its essential role in recruiting Cdc18 to DNA origins. Thus, we conclude that Sap1 is a replication-initiation factor that directly participates in the assembly of the pre-RC. DNA-replication origins in fission yeast are defined by possessing two essential elements with one bound by ORC and the other by Sap1.

Regulatory cis-elements are located in accessible promoter regions of the CAT2 promoter and affect activating histone modifications in Arabidopsis thaliana.

Catalase 2 (CAT2) plays an important role in the detoxification of hydrogen peroxide released either during photorespiration or as a consequence of biotic and abiotic stress as well as in the initiation of senescence. To date, our understanding of the regulation of CAT2 gene expression is rather poor. Chromatin immunoprecipitation experiments revealed that a wide region of the CAT2 promoter is nucleosome depleted, reflecting the ability to rapidly respond to changing environmental and stress conditions and, thus, adjusting the transcript levels of CAT2. The lowest nucleosome density was found in the region of -900 bp relative to the transcription initiation start (TIS) where two regulatory elements are located. The distance of the nucleosome depleted region to the TIS is quite unusual because the majority of nucleosome free regions are generally located in close vicinity to the 5' untranslated region. The analysis of transgenic 5' upstream deletion::gusA Arabidopsis lines showed that this region is important for the regulation of CAT2 promoter activity. To evaluate the function of the two motifs, the contribution of each element to CAT2 promoter activity was analyzed by site directed mutagenesis. The data revealed that the CAT2 promoter is regulated by the ACGT motif (Box2) rather than by the G-Box binding motif (Box1) in the vegetative phase of development. Furthermore, the presence of both Box1 and Box2 positively affected the abundance of activating histone modifications.

Epithelial Expression of Human ABO Blood Group Genes Is Dependent upon a Downstream Regulatory Element Functioning through an Epithelial Cell-specific Transcription Factor, Elf5.

The human ABO blood group system is of great importance in blood transfusion and organ transplantation. The ABO system is composed of complex carbohydrate structures that are biosynthesized by A- and B-transferases encoded by the ABO gene. However, the mechanisms regulating ABO gene expression in epithelial cells remain obscure. On the basis of DNase I-hypersensitive sites in and around ABO in epithelial cells, we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays and histone modifications indicated a novel positive regulatory element, designated the +22.6-kb site, downstream from ABO, and this was shown to enhance ABO promoter activity in an epithelial cell-specific manner. Expression of ABO and B-antigen was reduced in gastric cancer KATOIII cells by biallelic deletion of the +22.6-kb site using the CRISPR/Cas9 system. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that the site bound to an epithelial cell-specific transcription factor, Elf5. Mutation of the Ets binding motifs to abrogate binding of this factor reduced the regulatory activity of the +22.6-kb site. Furthermore, ELF5 knockdown with shRNA reduced both endogenous transcription from ABO and B-antigen expression in KATOIII cells. Thus, Elf5 appeared to be involved in the enhancer potential of the +22.6-kb site. These results support the contention that ABO expression is dependent upon a downstream positive regulatory element functioning through a tissue-restricted transcription factor, Elf5, in epithelial cells.

Coordinated Action of Two Double-Stranded RNA Binding Motifs and an RGG Motif Enables Nuclear Factor 90 To Flexibly Target Different RNA Substrates.

The mechanisms of how RNA binding proteins (RBP) bind to and distinguish different RNA molecules are yet uncertain. Here, we performed a comprehensive analysis of the RNA binding properties of multidomain RBP nuclear factor 90 (NF90) by investigating specifically the functional activities of two double-stranded RNA binding motifs (dsRBM) and an RGG motif in the protein's unstructured C-terminus. By comparison of the RNA binding affinities of several NF90 variants and their modes of binding to a set of defined RNA molecules, the activities of the motifs turned out to be very different. While dsRBM1 contributes little to RNA binding, dsRBM2 is essential for effective binding of double-stranded RNA. The protein's immediate C-terminus, including the RGG motif, is indispensable for interactions of the protein with single-stranded RNA, and the RGG motif decisively contributes to NF90's overall RNA binding properties. Conformational studies, which compared wild-type NF90 with a variant that contains a pseudophosphorylated residue in the RGG motif, suggest that the NF90 C-terminus is involved in conformational changes in the protein after RNA binding, with the RGG motif acting as a central regulatory element. In summary, our data propose a concerted action of all RNA binding motifs within the frame of the full-length protein, which may be controlled by regulation of the activity of the RGG motif, e.g., by phosphorylation. This multidomain interplay enables the RBP NF90 to discriminate RNA features by dynamic and adaptable interactions.

The complete mitochondrial genome of the Byasa alcinous (Lepidoptera: Papilionidae: Papilioninae).

The complete mitochondrial genome (mitogenome) of Byasa alcinous (Lepidoptera: Papilionidae: Papilioninae) is a circular molecule of 15,266 bp in length, containing 37 typical insect mitochondrial genes: 13 protein coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a non-coding AT-rich region. Its gene order and arrangement are identical to all other available butterfly mitogenomes. All PCGs start with a typical ATN initiation codon, except for COI, which is initiated by the CGA codon as observed in other butterfly species. Ten PCGs terminate in the complete stop codon TAA or TAG, whereas the COI, COII and ND4 genes end with single T. Ten intergenic spacers (73 bp in total), and 12 overlapping regions (28 bp in total) are dispersed throughout the whole genome. The non-coding AT-rich region is 405 bp long and contains some conserved structures similar to those found in other butterfly mitogenomes, such as the motif ATAGA followed by a 12-bp poly-T stretch and a microsatellite-like (AT)14 element preceded by the ATTTA motif. Additionally, a 11-bp poly-T sequences and a microsatellite-like (AT)7 repeated elements are detected in this region.

The complete mitochondrial genome of the Daimio tethys (Lepidoptera: Hesperoidea: Hesperiidae).

The complete mitochondrial genome of Daimio tethys (Hesperoidea: Hesperiidae) is a circular molecule of 15,341 bp in length, containing 37 typical animal mitochondrial genes: 13 protein coding genes (ATP6, ATP8, COI-III, ND1-6, ND4L, Cytb), 2 rRNA genes, 22 tRNA genes and a non-coding AT-rich region. Its gene order and content are identical to all other available butterfly mitogenomes. All PCGs initiate with typical ATN codons, except for COI, which is initiated by the CGA codon as observed in other butterfly species. Ten PCGs use complete termination codons TAA or TAG, whereas the COI, COII and ND5 genes end with a single T. A total of 179 bp of intergenic spacers are interspersed in 11 regions, ranging in size from 1 to 82 bp. The AT-rich region is 415 bp long and contains some conserved structures characteristic of the lepidopteran mitogenomes, including the motif ATAGA followed by a 17 bp poly-T stretch and a microsatellite-like (AT)8 element preceded by the ATTA motif.