Chantal Cauty
Institut national de la recherche agronomique
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Featured researches published by Chantal Cauty.
Developmental Dynamics | 2007
Denise Vizziano; Gwenaëlle Randuineau; Daniel Baron; Chantal Cauty
Early differentiation in rainbow trout gonads was investigated by expression profiling and in situ hybridization (ISH). Expression of cyp19a1 and fst in females and sox9a1 in males were sexually dimorphic between 32 to 35 days post‐fertilization (dpf). After 35 dpf, the differentiation proceeded with sexually dimorphic profiles for sox9a2, dmrt1, cyp11b2.1, amh in males and foxl2a, foxl2b, hsd3b1, inha in females. cyp17a1, cyp11a1, star, nr5a1b increased only after 40 dpf in both sexes with a slightly higher expression in females. cyp19a1 expression was localized in a cluster of somatic cells in the ventral side of female gonads, and sox9a2 and amh in somatic cells surrounding the germ cells, at 28 dpf and thereafter, both in male and female gonads. cyp11b2.1, cyp17a1, and cyp11a1 expressions were only detected in scattered somatic cells in males after 46 dpf. This confirms the early implication of cyp19a1 in trout ovarian differentiation and suggests that early testicular differentiation does not need androgen production. Developmental Dynamics 236:2198–2206, 2007.
Biology of Reproduction | 2008
Denise Vizziano; Daniel Baron; Gwenaëlle Randuineau; Sophie Mahe; Chantal Cauty
The present study was designed to obtain new insights into fish gonadal sex differentiation by comparing the effects of two different masculinizing treatments on some candidate gene expression profiles. Masculinization was induced in rainbow trout, Oncorhynchus mykiss, genetic all-female populations using either an active fish androgen (11betaAnd, 11beta-hydroxyandrostenedione) or an aromatase inhibitor (ATD, 1,4,6-androstatriene-3,17-dione). The expression profiles of 100 candidate genes were obtained by real-time RT-PCR, and 46 profiles displayed a significant differential expression between control populations (males and females) and ATD/11betaAnd-treated populations. These expression profiles were grouped in four temporally correlated expression clusters. Among the common responses shared by the two masculinizing treatments, the inhibition of some early female differentiating genes (cyp19a1, foxl2a, fst, and fshb) appears to be crucial for effective masculinization, suggesting that these genes act together via a short regulation loop to maintain high sex-specific ovarian expression of cyp19a1. This simultaneous down-regulation of female-specific genes could be triggered by some testicular genes, such as dmrt1, nr0b1 (also known as dax1), and pdgfra, which are quickly up-regulated by the two masculinizing treatments. In contrast to 11betaAnd, ATD quickly restored the expression levels of steroidogenesis related genes (cyp11b2.1, cyp11b2.2, hsd3b1, cyp17a, star, and nr5a1) and some Sertoli cell markers (sox9a2 and amh) to the expression levels observed during control testicular differentiation. This demonstrates that these genes are probably not needed for active masculinization and that the inhibition of endogenous estrogen synthesis produces a much more complete and specific testicular pattern of gene expression than that observed following androgen-induced masculinization.
Aquaculture | 1996
P. Tacon; P. Ndiaye; Chantal Cauty; F. Le Menn; Bernard Jalabert
Abstract The rhythm of ovarian development in Oreochromis niloticus was compared in females that had been allowed to, or were prevented from, mouthbrooding, respectively (INC for incubating females; NI for non incubating females). In both cases, fish were killed at 3-day intervals after spawning, throughout the duration of the reproductive cycle. Gonadal development was characterised either by calculating the gonadosomatic index (GSI) or by observing the distribution of ovarian follicle sizes larger than 600 μm, which is the minimum size required for vitellogenin deposition, as observed by immunocytochemistry. Six typical stages of ovarian development, highly correlated to the GSI, were defined and used as indicators in further studies. New batches of vitellogenic oocytes were shown to be already present at the time of spawning in both NI and INC females. Moreover, the shorter interspawning interval of NI females (15 instead of 27 days) together with the changes in GSI showed that vitellogenesis was accelerated when parental care was prevented. Finally, the GSI of parental females reached a plateau from day 12 to day 21, suggesting that ovarian development is slower during the guarding phase.
Environmental Biology of Fishes | 1994
Chantal Cauty; Alexis Fostier; Jacques Fuchs; Bernard Jalabert
SynopsisThe reproductive cycle and sex inversion of the protandrous, tropical seabass, Lates calcarifer, reared in seacages in French Polynesia, were studied. In Tahiti, this species exhibits a single annual reproductive period from October to February beginning with the warm and wet season. Sex inversion begins at the end of this reproductive period in post-spawning males. The main histological features of this process were: degeneration of testicular tissue, appearance of peripheral female germinal cells, and centripetal proliferation of ovarian tissue. Completion of sex inversion required profound morphological changes in the gonads because of the strong dimorphism that exists between testis and ovary. All transitional gonads appeared morphologically smaller than testes and typically had a red-pink colour. About 45% of the three-year-old male stock underwent sex inversion, and males averaged smaller in size than did females and transitional fish.
Biology of Reproduction | 2014
Johanna Bellaiche; Jean-Jacques Lareyre; Chantal Cauty; Ayaka Yano; Isabelle Allemand; Florence Le Gac
ABSTRACT Continuous or cyclic production of spermatozoa throughout life in adult male vertebrates depends on a subpopulation of undifferentiated germ cells acting as spermatogonial stem cells (SSCs). What makes these cells self-renew or differentiate is barely understood, in particular in nonmammalian species, including fish. In the highly seasonal rainbow trout, at the end of the annual spermatogenetic cycle, tubules of the spawning testis contain only spermatozoa, with the exception of scarce undifferentiated spermatogonia that remain on the tubular wall and that will support the next round of spermatogenesis. Taking advantage of this model, we identified putative SSCs in fish testis using morphological, molecular, and functional approaches. In all stages, large spermatogonia with ultrastructural characteristics of germinal stem cells were found, isolated or in doublet. Trout homologues of SSC and/or immature progenitor markers in mammals—nanos2 and nanos3, pou2, plzf, and piwil2—were preferentially expressed in the prepubertal testis and in the undifferentiated A spermatogonia populations purified by centrifugal elutriation. This expression profile strongly suggests that these genes are functionally conserved between fish and mammals. Moreover, transplantation into embryonic recipients of the undifferentiated spermatogonial cells demonstrated their high “stemness” efficiency in terms of migration into gonads and the ability to give functional gametes. Interestingly, we show that nanos2 expression was restricted to a subpopulation of undifferentiated spermatogonia (less than 20%) present as isolated cells or in doublet in the juvenile and in the maturing trout testis. In contrast, nanos2 transcript was detected in all the undifferentiated spermatogonia remaining in the spawning testis. Plzf was also immunodetected in A-Spg from spawning testis, reinforcing the idea that these cells are stem cells. From those results, we hypothesize that the subset of undifferentiated A spermatogonia expressing nanos2 transcript are putative SSC in trout.
Developmental Dynamics | 2005
F. Chauvigné; Chantal Cauty; Cécile Rallière; Pierre-Yves Rescan
Skeletal muscles are composed of different fiber types, largely defined by differential expression of protein isoforms involved in myofibrillogenesis or metabolism. To learn more about the gene activations that underlie the differentiation and the diversification of embryonic fish myotomal fibers, we investigated the developmental expression of 25 muscle genes in trout embryos by in situ hybridization of muscle‐specific transcripts. The earliest event of muscle differentiation, at approximately the 25‐somite stage, was the expression of a variety of muscle‐specific genes, including slow‐twitch and fast‐twitch muscle isoforms. The activation of these muscle genes started in the deep somitic domain, where the slow muscle precursors (the adaxial cells) were initially located, and progressively spread laterally throughout the width of the myotome. This mediolateral progression of gene expression was coordinated with the lateral migration of slow adaxial cells, which specifically expressed the slow myosin light chain 1 and the SLIM1/FHL1 genes. Subsequently, the fast and slow skeletal muscle isoforms precociously expressed in the course of the mediolateral wave of muscle gene activation became down‐regulated in the superficial slow fibers and the deep fast fibers, respectively. Finally, several muscle‐specific genes, including troponins, a slow myosin‐binding protein C, tropomodulins, and parvalbumin started their transcription only in late embryos. Taken together, these findings show in fish embryos that a common myogenic program is triggered in a mediolateral progression in all muscle cells. The acquisition of the slow phenotype involves the additional activation of several slow‐specific genes in migrating adaxial muscle cells. These events are followed by sequential gene activations and repressions in fast and slow muscle cells. Developmental Dynamics 233:659–666, 2005.
Comparative Biochemistry and Physiology B | 2009
P.-E. Mauger; Catherine Labbé; Julien Bobe; Chantal Cauty; I. Leguen; G. Baffet; P.Y. Le Bail
Comprehensive characterization of cultured cells in fish was little explored and cell origin is often deduced from morphological analogies with either epithelial of fibroblastic cells. This study aims to characterize cell origin in goldfish fin culture using morphological, immunochemical, and molecular approaches. Time lapse analysis revealed that cultured cell morphology changed within minutes. Therefore, cell morphology cannot predict whether cells are from fibroblastic or epithelial origin. The labeling pattern of heterologous anti-cytokeratin and anti-vimentin antibodies against goldfish epithelial cells and fibroblasts was first tested on skin sections and the corresponding labeling of the cultured cells was analyzed. No cell origin specificity could be obtained with the chosen antibodies. In the molecular approach, detection levels of three cytokeratin (CauK8-IIS, CauK49-IE and CauK50-Ie) and one vimentin transcripts were assessed on skin and fin samples. Specificity for epithelial cells of the most abundant mRNA, CauK49-Ie, was thereafter validated on skin sections by in situ hybridization. The selected markers were used afterwards to characterize fin cultures. CauK49-IE riboprobe labeled every cell in young cultures whereas no labeling was observed in older cultures. Accordingly, CauK49-IE transcript levels decreased after 15 days culture while CauK8-IIS ones increased. The use of homologous marker gave evidence that young cultured cells from goldfish fin are homogeneously of epithelial type and that cell characteristics may change over culture time.
Developmental Dynamics | 2005
Pierre-Yves Rescan; Cécile Rallière; F. Chauvigné; Chantal Cauty
Somites are repeated, epithelial structures that are derived from the unsegmented paraxial mesoderm located lateral to the notochord. In higher vertebrates, somites differentiate into a sclerotome that subsequently forms the vertebrae and the ribs and into a dermomyotome that gives rise to a myotome, from which arises the skeletal muscle, and to a dermatome, from which arises the dermis. Fish somites have been shown to produce a sclerotome and a myotome, but very little is known regarding their participation in the formation of connective tissues, especially at the junction between the epidermis and the myotome. To investigate the formation of connective tissues in fish somites, we have examined the expression pattern of the collagen I (α1) chain. As somitogenesis proceeds rostrocaudally, collagen I (α1) expression marks the sclerotomal cells and delineates the formation of the vertebrae. Surprisingly, after the completion of the segmentation, transcript for the collagen I (α1) chain appeared in a distinct epithelial‐like monolayer situated at the periphery of the developing somite facing the surface epidermis. This epithelial monolayer of somitic cells that covered the superficial slow muscle cells, did not express the myogenic transcriptional regulator myogenin and was devoid of contractile filament. As the somite increased in size, these collagen‐expressing epithelial cells flattened, forming a thin cellular layer underlying the epidermis and recovering the lateral surface of the myotome. In conclusion, the lateral domain of the fish somite forms a distinct epithelial cell layer sharing many characteristics with amniote dermatome. Developmental Dynamics 233:605–611, 2005.
The Journal of Experimental Biology | 2006
François Chauvigné; Cécile Rallière; Chantal Cauty; Pierre-Yves Rescan
SUMMARY Much of the present information on muscle differentiation in fish concerns the early embryonic stages. To learn more about the maturation and the diversification of the fish myotomal fibres in later stages of ontogeny, we investigated, by means of in situ hybridisation, the developmental expression of a large repertoire of muscle-specific genes in trout larvae from hatching to yolk resorption. At hatching, transcripts for fast and slow muscle protein isoforms, namely myosins, tropomyosins, troponins and myosin binding protein C were present in the deep fast and the superficial slow areas of the myotome, respectively. During myotome expansion that follows hatching, the expression of fast isoforms became progressively confined to the borders of the fast muscle mass, whereas, in contrast, slow muscle isoform transcripts were uniformly expressed in all the slow fibres. Transcripts for several enzymes involved in oxidative metabolism such as citrate synthase, cytochrome oxidase component IV and succinate dehydrogenase, were present throughout the whole myotome of hatching embryos but in later stages became concentrated in slow fibre as well as in lateral fast fibres. Surprisingly, the slow fibres that are added externally to the single superficial layer of the embryonic (original) slow muscle fibres expressed not only slow twitch muscle isoforms but also, transiently, a subset of fast twitch muscle isoforms including MyLC1, MyLC3, MyHC and myosin binding protein C. Taken together these observations show that the growth of the myotome of the fish larvae is associated with complex patterns of muscular gene expression and demonstrate the unexpected presence of fast muscle isoform-expressing fibres in the most superficial part of the slow muscle.
Sexual Development | 2013
Karina Valdivia; Brigitte Mourot; Elodie Jouanno; Jean-Nicolas Volff; Delphine Galiana-Arnoux; René Guyomard; Chantal Cauty; Béatrice Collin; Pablo Rault; Louise Hélary; Alexis Fostier; Edwige Quillet
Sex determination is known to be male heterogametic in the rainbow trout, Oncorhynchus mykiss; however, scattered observations that deviate from this rather strict genetic control have been reported. Here, we provide a detailed morphological and histological characterization of the gonadal differentiation and development (from 43 days postfertilization to 11 months of age) in an all-female (XX) population with a genetically governed masculinization phenotype. In comparison with control males and females, the gonadal differentiation in these animals was characterized by many perturbations, including significantly fewer germ cells. This decrease in germ cells was confirmed by the significantly decreased expression of 2 germ cell maker genes (vasa and sycp3) in the masculinized XX populations as compared with the control females and control males. Although only a proportion of the total adult population was partially or fully masculinized, this early differentiating phenotype affected nearly all the sampled animals. This suggests that the adult masculinization phenotype is the consequence of an early functional imbalance in ovarian differentiation in the entire population. We hypothesize that the lower number of germ cells that we observed in this population could be one cause of their masculinization.