Molecular phylogeny reveals the repeated evolution of complex male genital traits in the New Zealand moth genus Izatha (Lepidoptera: Xyloryctidae)

Male genitalia are among the most rapidly evolving and divergent morphological structures and sexual selection is known to drive this phenomenon in many taxa. Because of their diversity, even within a single genus, genital characters are frequently used to infer relationships among closely‐related species. Moths within the genus Izatha (Xyloryctidae) are ideal candidates for investigating the phylogenetic patterns of genital evolution as they display great variation in male genital structure and complexity. We determined the evolutionary relationships among 31 species of Izatha by constructing a molecular phylogeny of the genus based on the mitochondrial cytochrome oxidase subunit I gene and the isocitrate dehydrogenase and carbamoylphosphate synthase domain protein nuclear genes. This allowed estimations of ancestral male genital character states and patterns of male genital diversification using maximum‐likelihood models. The genus is divided into two well‐supported clades and two poorly supported clades at the root of the phylogeny with incomplete phylogenetic resolution within two species groups, likely due to rapid speciation. Izatha display a number of apomorphic phallic traits including cornuti (sclerotized spines) which are either discharged into the female during copulation (deciduous cornuti) or fixed to the male phallus (compound and fish‐hook cornuti). Within the genus, there is a reduction of secondary genital characters – the uncus and gnathos – but an elaboration of another grasping structure, the juxta; the potential origin and functionality of these male genital traits are discussed. Overall, some male genital characters provided a good indication of species relationships; however, several parts of the complex male genitalia of Izatha show evidence of homoplasy and convergence highlighting the problems of using these traits in determining species relationships. Additionally, this convergence has highlighted that complex genital structures may evolve repeatedly and independently within a lineage.     

GENUS EROTIS MEYRICK (LEPIDOPTERA: OECOPHORIDAE) NEW FOR CHINA

Abstract  This paper reports the genus Erotis Meyrick for the first time from China. Two new species Erotis expansa sp. nov. and Erotis punctalosa sp. nov. are described. E. expansa sp. nov. is related to E. phosphora Meyrick both in appearance and in the male genitalia, but can be differentiated from the latter by uncus broader and slightly concave at middle of caudal margin, gnathos nearly as long as uncus and valva with costa almost straight in the male genitalia. E. punctalosa resembles E. expansa sp. nov. externally, but can be easily distinguished from the latter by the female genitalia: eighth tergite caudally almost straight; two signa large thorn-like, basal plate irregularly triangular in shape, with fine spines along anterior margin. The photographs of the adults and the genital structures of the new species are provided. A key to all the known species of Erotis is given.     

中国新纪录属——平织蛾属Erotis(鳞翅目:织蛾科)研究(英文)

首次报道了平织蛾属Erotis Meyrick在中国的分布,并描述了2新种:阔平织蛾Erotis expansasp.nov.和点平织蛾Erotis punctalosa sp.nov.。阔平织蛾采自贵州江口,与Erotis phosphoraMeyrick相似,但其雄性外生殖器的爪形突较宽大,后缘中部微凹;颚形突几乎与爪形突等长;抱器背平直。点平织蛾采自广西防城,与阔平织蛾Erotis expansa sp.nov.外形近似,但其雌性第八腹节背板后缘较平直;囊突角状,基部骨化板为不规则三角形,其前缘有微刺。文中给出了该属世界已知种检索表。模式标本保存在南开大学生物系。     

草地螟雄蛾生殖系统的形态和结构

针对目前关于草地螟Loxostege sticticalis L.雄成虫生殖系统结构和功能的研究相对缺乏的状况,本文利用光镜和扫描电镜系统研究了草地螟雄蛾的内外生殖器官及相关结构。草地螟雄蛾内外生殖器官集中于腹部第5¹0腹节;内生殖器官位于510腹节;内生殖器官位于5⁸腹节内腔中,由睾丸(testes)、贮精囊(seminal vesicle)、输精管(vas deferens)、附腺(accessory gland)和射精管(ejaculatory ducts)组成;外生殖器官为腹部第9、10腹节的特化结构,包括抱握器(harpes)、背兜(tegumen)、基腹弧(vinculum)、钩形突(uncus)、颚形突(gnathos)、阳茎囊(aedeagal caecum)和阳茎(phallus)。外生殖器中抱握器的端刺(furcella)方向为雄蛾区别于其它种类的一个重要形态学特征。该研究首次明确了草地螟雄蛾的生殖系统结构,并为锥额野螟蛾属中种间分类提供更多的科学依据。     

The use of muscle morphology of Chrysopolomidae (Lepidoptera) genitalic appendages in developing a family system

The male genitalia of Chrysopolomidae were found to include by nine pairs of muscles: m1, m2(10), m3(2), m4, m5(7), m6(5), m7(6), m8(3), m20, and the unpaired muscle m21, fully corresponding to their ground plan in Zygaenoidea. The archaic muscles m20 were found in both Chrysopolomidae and Limacodidae, for the first time for the superfamily Zygaenoidea. Muscles m3(2) and m4 in all the studied chrysopolomids are attached to the base of a gnathos-like complex sclerite, which proves its origin from the transtilla. The genital apparatus of Chrysopolomidae and its muscles are completely symmetrical. The bases of intravalval muscles m5(7) have moved from the sacculus to the juxta; this feature is not found in any other related family of the limacoid complex. The gnathos of Chrysopolomidae is reduced and functionally replaced by the transtilla separated from the valvae; some parts of the true gnathos may be incorporated in the gnathos-like structure of the transilla. A characteristic feature is the presence of strong muscles m3(2), which are reduced in all the studied limacodids. These muscles are running from the modified transtilla deep inside the uncus and provide not the abduction of the valvae but the depression of the uncus and the lifting of the arms of the transtilla. Thus, Chrysopolomidae are morphologically separated from Limacodidae; it is suggested that the former group should be treated as a separate family closely related to Limacodidae. The tribe Achroceridini is transferred from Chrysopolominae into Ectropinae based on the similar structure of the male genitalia and the presence of two pairs of spurs on the hind tibia.     

Ontogeny of the jaws of monogonont rotifers: the malleate trophi of Rhinoglena and Proalides (Ploima,Epiphanidae)

Information on the embryonic development of the malleate trophi in Epiphanidae (Rotifera, Monogononta, Ploima) is presented, based on scanning electron microscopy observations in Rhinoglena fertoeensis, R. frontalis, R. kutikovae, R. tokioensis, and Proalides tentaculatus, to contribute to the understanding of this structure of high evolutionary and functional relevance in Rotifera. The first observable and distinctly sclerotized structures were a double row of median transversal sclerites along the longitudinal axis, wherein the future unci, rostellar scleropili, cristae rami, and basal apophyses became recognizable. Fulcrum and manubria arose subsequently; the fulcrum sclerites were longitudinally ordered in a double layer. The rami chambers developed last as lamellar structures. Unci appeared as separate thin, elongate elements, the primary uncini, developing to uncus plates by transversal growth and apposition of sclerite material on the shafts of the uncini. The heads of the uncini showed their greatest development after fusion of their shafts into uncus plates. The interjacent spaces between the heads functioned as a mold, organizing bundles of sclerites which developed into the uniseriate, zigzag‐shaped cristae rami. The fulcrum attained its definite shape by elongation of the double layer of rod‐shaped sclerites into appressed sclerofibrillae. Manubria became visible as a proximal ridge of sclerites, whereupon a triangular lamella composed of crisscross‐oriented sclerites developed distally, growing out to the manubrial chambers. Ramus chambers originated from two longitudinal amorphous lamellae incorporating the median rami sclerites and closing from distal to proximal; subbasal chambers were formed before the basal chambers.     

Sequential Expression of Nucleoproteins during Rat Spermiogenesis

Transition proteins and protamines are highly basic sperm-specific nuclear proteins that serve to compact the DNA during late spermiogenesis. To understand their sequential role in this function, transition protein 1 (TP1), transition protein 2 (TP2), and protamine 1 (P1) were assayed by polyacrylamide gel electrophoresis in pools of microdissected, staged seminiferous tubule segments in the rat. The results were compared with immunocytochemical analyses of squash preparations from accurately identified stages of the epithelial cycle. TP2 was the first to appear as a faint band at stages IX–XI, followed by high levels at stages XII–XIV of the cycle. TP1 showed a low expression at stage XII of the cycle and peaked at stages XIII–I, whereas protamine 1 first appeared at stage I of the cycle and remained high throughout the rest of spermiogenesis. Immunocytochemical analyses and Western blots largely confirmed these results: TP2 in steps 9–14, TP1 in steps 12–15, and P1 from late step 11 to step 19 of spermiogenesis. We propose that TP2 is the first nucleoprotein that replaces histones from the spermatid nucleus, and its appearance is associated with the onset of nuclear elongation. TP1 shows up along with the compaction of the chromatin. The two transition proteins seem to have distinct roles during transformation of the nuclei and compaction of spermatid DNA.     

Chemicals to induce plastid signals in Arabidopsis seedlings

Abstract

Tetrapyrroles and abscisic acid (ABA) were considered as plastid signal molecules for plant cells. However, they attract hot controversies. High levels of sugars also trigger plastid signals to regulate nuclear gene expression. However, the effective concentrations of sugar are extremely high (100–10,000 times of tetrapyrroles). To resolve these controversies and inconsistencies, we investigated which chemicals at what concentrations may work as plastid signal molecules, and summarize their common chemical structures. We found that they can be classified into two categories: (1) tetrapyrroles or other carbon–nitrogen heterocyclic compounds with an adjacent three-membered ring (two of them may be incomplete), with a signaling impact order: Mg–protoporphyrin IX/ABA>Fe–protoporphyrin IX>Zn–protoporphyrin IX>protoporphyrin IX>tryptophan>histidine. The completeness of the rings with a chelated metal ion has a positive effect on the effectiveness of plastid signaling stimulation. (2) Sugar or other carbon–oxygen (sulfur) five- or six-membered ring compounds, such as cyclohexane and thiophene. The effective concentrations of the second category of signal molecules are very high (about 400 mM for the monosaccharide). The two types of signal molecules are possibly perceived by different receptors in the plastid.     

Congruence between comparative morphology and molecular phylogenies: the final stage of evolution of the skeletal characters of male genitalia in the subtribe Polyommatina (Lepidoptera,Lycaenidae). Part 2. Uncus and subunci

The morphology of the male terminalia (uncus and subunci) was studied in 39 species of the subtribe Polyommatina (Lycaenidae). Traces of nine established characters were mapped on the molecular phylogeny of the subtribe proposed by Talavera et al. (2013). The ancestral character states for these morphological structures were established in Plebejus s. l. and Polyommatus s. l. According to the time calibration of the proposed molecular tree, the studied skeletal structures (uncus and subunci) evolved very slowly within the last million years. It was shown that the similar shape of the uncus and subuncus branches arose independently and underwent parallel morphological transformations. In particular, wide and, as a rule, ventrally directed uncus lobes arose independently in Polyommatus s. str., Alpherakya, Glabroculus, and Aricia. Yet, in various evolutionary lines of Polyommatina similar changes in the length ratio of the proximal and distal parts of the subunci as well as in the shape of their apical hooks were observed. The character states marking the groups Polyommatus s. str. and Aricia were established. The evolutionary changes in the uncus morphology were highly non-uniform in the various monophyletic lines of Polyommatina. As a result, representatives of some “old” lines have more specialized features of the uncus morphology in comparison with those belonging to “young” lines that retain ancestral character states. In Polyommatina, the transformation of the male terminalia was directed toward development of the most effective mechanism of female fixation during copulation. This goal was reached in similar ways in various evolutionary lines of Polyommatina, which explains numerous parallelisms in morphology of these structures.     

Fine structure of the gnathosoma of Archegozetes longisetus Aoki (Acari: Oribatida,Trhypochthoniidae)

Oribatida are one of the main groups of Acari comprising mostly important decomposers in soils. Most species are particle feeders, an exceptional mode of nutrition in Arachnida. Hence, their feeding organs, the gnathosoma, are of special functional interest. We studied nearly all components using scanning and transmission electron microscopies as well as reconstructions based on synchrotron X‐ray microtomography from the model oribatid Archegozetes longisetosus. Besides cuticular structures, we describe the full set of muscles and confirm the presence of a trochanter remnant at the base of the chelicera. Setae on the prodorsum and the anterior and posterior infracapitular setae are mechanoreceptors innervated by two dendrites ending with tubular bodies. Dendrites of adoral setae, anterior setae of the chelicerae, and the supracoxal setae show neither obvious tubular bodies nor wall or terminal pores. Thus their function remains obscure. For the first time, a muscular proprioreceptor has been found in Arachnida. It likely monitors the actions of muscles moving the movable digit of the chelicera. Glandular structures within and associated with the gnathosoma are described. Dermal glands represented by secretory porose areas are found within the infracapitulum. More complex associated glands comprise the podocephalic glands and the infracapitular glands, the ducts of which were traced completely for the first time. The components described are mostly fundamental for the gnathosoma of Actinotrichida (Acariformes), one of the two lineages of Acari, to which Oribatida belong. The gnathosoma is generally considered the most relevant putative synapomorphy of Acari. Since the monophyly of Acari has become more and more questionable during the last decades, a thorough reinvestigation of this body part is necessary for a comprehensive understanding of acarine and even arachnid phylogeny and evolution. This article provides a starting point of such a re‐evaluation of the gnathosoma. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.     

水蜡蛾一新属一新种：（鳞翅目：水蜡蛾科）

Brahmaea属是Walker(1855)以Bombyx certhia Fabricius为模式种成立的。Mell(1929)根据成虫形态特征、后翅翅脉的差异(有无连接Sc+R_1和Rs脉的横脉),将亚洲的水蜡蛾分为二群,建立一个新亚属 Brahmophthalma Mell并绘有Brahmaea Walker属与新亚属内每个种的翅脉简图以示区别;Bryk(1949)将Brahmophthalma提升为属。我们在整理和研究水蜡蛾的标本中,发现Brahmaea Walker属中实际存在着成虫形态和外生殖器差别很大的两个类群,作者认为有必要将其分为两个属,建立一个新属,并记述一新种。     

A gentle method for the preparation of hard parts (trophi) of the mastax of rotifers and scanning electron microscopy of the trophi ofBrachionus plicatilis (Rotifera)

Summary Trophi of the rotiferBrachionus plicatilis were prepared by dissolving rotifer tissues and lorica with sodium dodecyl sulfate (SDS) and dithiothreitol (DTT) and were examined by scanning electron microscopy in order to obtain information on the functional morphology of these structures. The trophi are not composed of distinct parts but form a continuous structure of rigid pieces and connecting membranous regions. The membranous components allow movements of the rigid parts against each other and/or restrict the extent of such movements. The main hinge for the movement of the trophi is the membranous connection between the two rami; movements of rami and unci occur together since these parts are tightly connected by two narrow membranes in the subuncus region. The subunci seem to constitute masticating devices which act against grooved ridges of the rami and might make it feasible to disintegrate nutrient particles to as small as 1 m. Crushing of coarser nutrients might be performed by the opposite surfaces of the two rami.Abbreviations br bulla rami - c crest along the ventral surface of the manubrium - cd distal part of the manubrium (cauda) - cv proximal part of the manubrium (clava) - d1 entrance from the bowl-shaped recess at the dorsal side of the manubrium into one of the (three) cavities within the proximal part of the manubrium - d2 second dorsal entrance into one of the (three) cavities within the proximal part of the manubrium - eu edge at the distal end of the uncus which fits into a notch at the proximal end of the manubrium - gr small, oblong grooves at the distal surface of the reinforced projecting ridges of the rami - f fulcrum - h hinge between the two rami - l ligaments extending from the central membranes to the dorsal surfaces of the unci - m central membranous structures - ma manubrium - p partition between the cavities within the ramus - ps large, proximal surfaces of the rami - r ramus - rd reinforced ridge on the anterio/dorsal part of the ramus - rv ventral, triangular surface of the ramus - su subuncus - sur root-like structures connecting the subuncus with the uncus plate - t teeth-like proximal endings of the uncus ridges - u uncus - um membranous connection between uncus and manubrium - ur membranous connection between uncus and ramus in the subuncus region - uvr ridges on the ventral side of the uncus - ve ventral entrance into one of the (three) cavities within the proximal part of manubrium     

The genitalia of termites (isoptera): Possibilities of using in taxonomy

An attempt has been made to use some structures of the external genitalia in the taxonomy of termites. Twenty-five species of four largest families were examined. Only the female external genitalia appeared to be suitable for identification of species, with some genital structures (medisternite, basivalvae, parasternites, etc.) being most important for these purposes. The taxonomic suitability of these structures is different in different families. In the family Kalotermitidae, the medisternite and spermathecal opening are strongly sclerotized and suitable for the species identification, whereas the basivalvae are reduced or lost. In Hodotermitidae, the basivalvae are well-developed and their shape is different in different species. Structural features of the basivalvae and spermathecal opening are species-specific in Rhinotermitidae, the shape of the basivalvae and position of the spermathecal opening, in Termitidae. In addition, species of Termitidae have a characteristic strigation of the basivalvae. In Macrotermitinae and Nasutitermitinae, the anterior margins of sternite IX are well sclerotized and form parasternites. The structures proposed by us as diagnostic vary only within species.     

Structural basis of competitive recognition of p53 and MDM2 by HAUSP/USP7: implications for the regulation of the p53-MDM2 pathway

Herpesvirus-associated ubiquitin-specific protease (HAUSP, also known as USP7), a deubiquitylating enzyme of the ubiquitin-specific processing protease family, specifically deubiquitylates both p53 and MDM2, hence playing an important yet enigmatic role in the p53–MDM2 pathway. Here we demonstrate that both p53 and MDM2 specifically recognize the N-terminal tumor necrosis factor–receptor associated factor (TRAF)–like domain of HAUSP in a mutually exclusive manner. HAUSP preferentially forms a stable HAUSP–MDM2 complex even in the presence of excess p53. The HAUSP-binding elements were mapped to a peptide fragment in the carboxy-terminus of p53 and to a short-peptide region preceding the acidic domain of MDM2. The crystal structures of the HAUSP TRAF-like domain in complex with p53 and MDM2 peptides, determined at 2.3-Å and 1.7-Å resolutions, respectively, reveal that the MDM2 peptide recognizes the same surface groove in HAUSP as that recognized by p53 but mediates more extensive interactions. Structural comparison led to the identification of a consensus peptide-recognition sequence by HAUSP. These results, together with the structure of a combined substrate-binding-and-deubiquitylation domain of HAUSP, provide important insights into regulation of the p53–MDM2 pathway by HAUSP.     

Tsukiyamaia,a new genus of the tribe Baorini (Lepidoptera,Hesperiidae, Hesperiinae)

Skippers of the tribe Baorini are evidently a monophyletic group in the subfamily Hesperiinae. In this study, a new Baorini member Tsukiyamaia albimacula gen. n. et sp. n. is described from north Myanmar, southwest China and north Vietnam. Despite its peculiar and striking wing-pattern, this new genus has some important characters of Baorini, such as a broad and bifid uncus and a well-developed gnathos. Based on an analysis of male genitalia and the molecular phylogenies inferred from both mitochondrial and nuclear genes (28 taxa, total aligned length: 2968 bp), it is proposed that the genus Tsukiyamaia is closely related to the genus Polytremis, which has high species diversity in China. This study not only describes a new skipper but also highlights that Tsukiyamaia is important in clarifying phylogenetic relationship of Polytremis and its allies.     

Genital morphology of the haplogyne spider <Emphasis Type="Italic">Harpactea lepida</Emphasis> (Arachnida,Araneae, Dysderidae)

Female Harpactea lepida possess a single genital opening leading into a diverticulum. This diverticulum shows no secretory layer. It continues posteriorly into a receptaculum which is associated with gland cells. In the two already described dysderids, Dysdera crocata and D. erythrina, the bilobed spermatheca lies anteriorly to the diverticulum. Gland cells are associated with the spermatheca and the diverticulum. In H. lepida, the sclerotized genital structures lie dorsally to the diverticulum and consist of a posterior and an anterior part. The posterior part shows a lamella extending laterally to sclerites functioning as muscle attachments. The anterior part has two roundish structures. A hollow stalk-like sclerite functioning as muscle attachment extends towards anterior. The posterior and the anterior part of the sclerotized genital structures fit together. A narrow uterine valve connecting the uterus externus with the diverticulum forms between them. It may be opened by muscles as also suggested for D. erythrina. In H. lepida, spermatozoa embedded in secretion are found in the diverticulum and the receptaculum. There is no evidence that they are stored under different conditions like in D. erythrina. Additional spermatozoa are found in the uterus externus of H. lepida which could be an indication for internal fertilization. Spermatogenesis occurs in cysts in the testes of male H. lepida. In the vasa deferentia, the ductus ejaculatorius and the palpal bulb, the spermatozoa are embedded in homogenous secretion. The palpal bulb has a distal extension bearing a crown-like structure. The embolus is situated at the base of the extension. In memoriam of Konrad Thaler.     

The principal structure of male genital sclerites and muscles of bombycoid moths, with special reference to Anthelidae (Lepidoptera: Bombycoidea)

Male genital structures and muscles of bombycoid moths have repeatedly been misidentified in the literature. Furthermore, the genital structures of some bombycoid families, such as the poorly known Australo-New Guinean Anthelidae, have essentially remained unstudied. Based on comparative morphology, this study details the principal arrangements of male genital sclerites and muscles in all bombycoid families, with particular focus on basic structures and their modifications in Anthelidae. Emphasis is placed on the homology of and fusions between these structures and their function, providing a basis for the interpretation of modifications in future phylogenetic and taxonomic studies. This includes the unique fusion of gnathos and valvae in several bombycoid families, the arrangement and extent of the fused tegumen and vinculum, as well as the homology of the "transtilla". Further, a modification of the valve adductor muscle (the segment IX sternum to valva muscle, m4) widely regarded as a synapomorphy of Bombycoidea is demonstrated to be non-existent, as is the presumed presence of the valve abductor muscle (the segment IX tergum to valva muscle, m2) in Saturniidae.     

Calicotyle hydrolagi n. sp. (Monogenea: Monocotylidae) infecting the deep-sea Eastern Pacific black ghost shark Hydrolagus melanophasma from the Atacama Trench,with comments on host specificity of Calicotyle spp.

We describe Calicotyle hydrolagi n. sp. (Monogenea: Monocotylidae) infecting the cloaca of deep-water Eastern Pacific black ghost sharks, Hydrolagus melanophasma captured as bycatch at a local fishery for Patagonian toothfish Dissostichus eleginoides, (Nototheniidae) in the Atacama Trench using morphological and nucleotide (LSU rRNA and SSU rRNA) data. This new species is differentiated from its congeners by a number of characters, including the absence of a cecal diverticula, the size and shape of the male copulatory organ and the shape of the vagina, as well as by differences in molecular data (SSU rRNA and LSU rRNA). The suitability of some sclerotized structures such as the male copulatory organ (MCO) as a taxonomic character is discussed; specifically, we found that the relationship between MCO and total length exhibit different trends in members of Calicotyle isolated from sharks, skates and chimaeras. Additional efforts to obtain sample of Calicotyle species and further molecular studies based on ribosomal and mitochondrial genes are necessary to clarify the degree of host specificity in this genus. Additionally, this is the first report of a member of Calicotyle to be reported in the Southeastern Pacific Ocean.     

Array CGH characterization of an unbalanced X-autosome translocation associated with Xq27.2–qter deletion, 11q24.3–qter duplication and Xq22.3–q27.1 duplication in a girl with primary amenorrhea and mental retardation

We present array comparative genomic hybridization (aCGH) characterization of an unbalanced X-autosome translocation with an Xq interstitial segmental duplication in a 16-year-old girl with primary ovarian failure, mental retardation, attention deficit disorder, learning difficulty and facial dysmorphism. aCGH analysis revealed an Xq27.2–q28 deletion, an 11q24.3–q25 duplication, and an inverted duplication of Xq22.3–q27.1. The karyotype was 46,X,der(X)t(X;11)(q27.2;q24.3) dup(X)(q27.1q22.3). We discuss the genotype–phenotype correlation in this case. Our case provides evidence for an association of primary amenorrhea and mental retardation with concomitant unbalanced X-autosome translocation and X chromosome rearrangement.     

Identification and characterization of a sphere organelle protein

Sphere organelles are nuclear structures in amphibian oocytes that are easily visible by light microscopy. These structures are up to 10 microns in diameter and have been described morphologically for decades, yet their function remains obscure. The present study defines a protein component of the sphere organelle, named SPH-1, which is recognized by a mAb raised against purified Xenopus laevis oocyte nucleoplasm. SPH-1 is an 80-kD protein which is localized specifically to spheres and is undetectable elsewhere on lampbrush chromosomes or in nucleoli. We show using confocal microscopy that SPH-1 is localized to the cortex of sphere organelles. Furthermore, we have isolated a cDNA that can encode SPH-1. When epitope-tagged forms of SPH-1 are expressed in X. laevis oocytes the protein specifically localizes to spheres, demonstrating that the cloned cDNA encodes the sphere antigen. Comparison of the predicted amino acid sequence with sequence databases shows SPH-1 is related to p80-coilin, a protein associated with coiled bodies; coiled bodies are nuclear structures found in plant and animal cells. The sphere-specific mAb stains X. laevis tissue culture cells in a punctate nuclear pattern, showing that spheres or sphere antigens are present in somatic cells as well as germ cells and suggesting a general and essential function for spheres in all nuclei.