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Molecular characterization and expression analysis of five different elongation factor 1 alpha genes in the flatfish Senegalese sole (Solea senegalensis Kaup): differential gene expression and thyroid hormones dependence during metamorphosis.

ABSTRACT: BACKGROUND: Eukaryotic elongation factor 1 alpha (eEF1A) is one of the four subunits composing eukaryotic translation elongation factor 1. It catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome in a GTP-dependent manner during protein synthesis, although it also seems to play a role in other non-translational processes. Currently, little information is still available about its expression profile and regulation during flatfish metamorphosis. With regard to this, Senegalese sole (Solea senegalensis) is a commercially important flatfish in which eEF1A gene remains to be characterized. RESULTS: The development of large-scale genomics of Senegalese sole has facilitated the identification of five different eEF1A genes, referred to as SseEF1A1, SseEF1A2, SseEF1A3, SseEF1A4, and Sse42Sp50. Main characteristics and sequence identities with other fish and mammalian eEF1As are described. Phylogenetic and tissue expression analyses allowed for the identification of SseEF1A1 and SseEF1A2 as the Senegalese sole counterparts of mammalian eEF1A1 and eEF1A2, respectively, and of Sse42Sp50 as the ortholog of Xenopus laevis and teleost 42Sp50 gene. The other two elongation factors, SseEF1A3 and SseEF1A4, represent novel genes that are mainly expressed in gills and skin. The expression profile of the five genes was also studied during larval development, revealing different behaviours. To study the possible regulation of SseEF1A gene expressions by thyroid hormones (THs), larvae were exposed to the goitrogen thiourea (TU). TU-treated larvae exhibited lower SseEF1A4 mRNA levels than untreated controls at both 11 and 15 days after treatment, whereas transcripts of the other four genes remained relatively unchanged. Moreover, addition of exogenous T4 hormone to TU-treated larvae increased significantly the steady-state levels of SseEF1A4 with respect to untreated controls, demonstrating that its expression is up-regulated by THs. CONCLUSION: We have identified five different eEF1A genes in the Senegalese sole, referred to as SseEF1A1, SseEF1A2, SseEF1A3, SseEF1A4, and Sse42Sp50. The five genes exhibit different expression patterns in tissues and during larval development. TU and T4 treatments demonstrate that SseEF1A4 is up-regulated by THs, suggesting a role in the translational regulation of the factors involved in the dramatic changes that occurs during Senegalese sole metamorphosis.

SUBMITTER: Infante C

PROVIDER: S-EPMC2270864 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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Molecular characterization and expression analysis of five different elongation factor 1 alpha genes in the flatfish Senegalese sole (Solea senegalensis Kaup): differential gene expression and thyroid hormones dependence during metamorphosis.

Infante Carlos C Asensio Esther E Cañavate José Pedro JP Manchado Manuel M

BMC molecular biology 20080130

<h4>Background</h4>Eukaryotic elongation factor 1 alpha (eEF1A) is one of the four subunits composing eukaryotic translation elongation factor 1. It catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome in a GTP-dependent manner during protein synthesis, although it also seems to play a role in other non-translational processes. Currently, little information is still available about its expression profile and regulation during flatfish metamorphosis. With regard to this, Senegale ...[more]

PMID: 18234081

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Project description:BACKGROUND: Keratins make up the largest subgroup of intermediate filaments, and, in chordates, represent the most abundant proteins in epithelial cells. They have been associated with a wide range of functions in the cell, but little information is still available about their expression profile and regulation during flatfish metamorphosis. Senegalese sole (Solea senegalensis) is a commercially important flatfish in which no keratin gene has been described yet. RESULTS: The development of large-scale genomics of Senegalese sole has facilitated the identification of two different type I keratin genes referred to as sseKer1 and sseKer2. Main characteristics and sequence identities with other fish and mammal keratins are described. Phylogenetic analyses grouped sseKer1 and sseKer2 in a significant clade with other teleost epidermal type I keratins, and have allowed for the identification of sseKer2 as a novel keratin. The expression profile of both genes was studied during larval development and in tissues using a real-time approach. sseKer1 and sseKer2 mRNA levels were significantly higher in skin than in other tissues examined. During metamorphosis, sseKer1 transcripts increased significantly at first stages, and reduced thereafter. In contrast, sseKer2 mRNA levels did not change during early metamorphosis although a significant drop at metamorphosis climax and late metamorphosis was also detected. To study the possible regulation of sseKer gene expressions by thyroid hormones (THs), larvae were exposed to the goitrogen thiourea (TU). TU-treated larvae exhibited higher sseKer1 and sseKer2 mRNA levels than untreated control at both 11 and 15 days after treatment. Moreover, addition of exogenous T4 hormone to TU-treated larvae restored or even reduced the steady-state levels with respect to the untreated control, demonstrating that expression of both genes is negatively regulated by THs. CONCLUSION: We have identified two keratin genes, referred to as sseKer1 and sseKer2, in Senegalese sole. Phylogenetic analyses revealed sseKer2 as a novel keratin. Although they exhibit different expression patterns during larval development, both of them are negatively regulated by THs. The co-regulation by THs could explain the reduction of both keratin transcripts after the metamorphosis climax, suggesting their role in the tissue remodelling processes that occur during metamorphosis.

Project description:The retinas of nonmammalian vertebrates have cone photoreceptor mosaics that are often organized as highly patterned lattice-like distributions. In fishes, the two main lattice-like patterns are composed of double cones and single cones that are either assembled as interdigitized squares or as alternating rows. The functional significance of such orderly patterning is unknown. Here, the cone mosaics in two species of Soleidae flatfishes, the common sole and the Senegalese sole, were characterized and compared to those from other fishes to explore variability in cone patterning and how it may relate to visual function. The cone mosaics of the common sole and the Senegalese sole consisted of single, double, and triple cones in formations that differed from the traditional square mosaic pattern reported for other flatfishes in that no evidence of higher order periodicity was present. Furthermore, mean regularity indices for single and double cones were conspicuously lower than those of other fishes with "typical" square and row mosaics, but comparable to those of goldfish, a species with lattice-like periodicity in its cone mosaic. Opsin transcripts detected by quantitative polymerase chain reaction (sws1, sws2, rh2.3, rh2.4, lws, and rh1) were uniformly expressed across the retina of the common sole but, in the Senegalese sole, sws2, rh2.4, and rh1 were more prevalent in the dorsal retina. Microspectrophotometry revealed five visual pigments in the retina of the common sole [S(472), M(523), M(536), L(559), and rod(511)] corresponding to the repertoire of transcripts quantified except for sws1. Overall, these results indicate a loss of cone mosaic patterning in species that are primarily nocturnal or dwell in low light environments as is the case for the common sole and the Senegalese sole. The corollary is that lattice-like patterning of the cone mosaic may improve visual acuity. Ecological and physiological correlates derived from observations across multiple fish taxa that live in low light environments and do not possess lattice-like cone mosaics are congruent with this claim.

Project description:Dominance is defined as the preferential access to limited resources. The present study aimed to characterise dominance in a non-aggressive flatfish species, the Senegalese sole (Solea senegalensis) by 1) identifying dominance categories and associated behaviours and 2) linking dominance categories (dominant and subordinate) with the abundance of selected mRNA transcripts in the brain. Early juveniles (n = 74, 37 pairs) were subjected to a dyadic dominance test, related to feeding, and once behavioural phenotypes had been described the abundance of ten selected mRNAs related to dominance and aggressiveness was measured in the brain. Late juveniles were subjected to two dyadic dominance tests (n = 34, 17 pairs), related to feeding and territoriality and one group test (n = 24, 4 groups of 6 fish). Sole feeding first were categorized as dominant and sole feeding second or not feeding as subordinate. Three social behaviours (i. "Resting the head" on another fish, ii. "Approaching" another fish, iii. "Swimming above another" fish) were associated with dominance of feeding. Two other variables (i. Total time occupying the preferred area during the last 2 hours of the 24 h test, ii. Organisms occupying the preferred area when the test ended) were representative of dominance in the place preference test. In all tests, dominant fish compared to subordinate fish displayed a significantly higher number of the behaviours "Rest the head" and "Approaches". Moreover, dominant sole dominated the sand at the end of the test, and in the group test dominated the area close to the feed delivery point before feed was delivered. The mRNA abundance of the selected mRNAs related to neurogenesis (nrd2) and neuroplasticity (c-fos) in dominant sole compared to subordinate were significantly different. This is the first study to characterise dominance categories with associated behaviours and mRNA abundance in Senegalese sole and provides tools to study dominance related problems in feeding and reproduction in aquaculture.

Project description:BackgroundOrganophosphate pesticides-OP-, like malathion, can alter the normal functioning of neuro-endocrine systems (e.g., hypothalamus-pituitary-thyroid-HPT- axis), and to interfere on the thyroidal homeostasis. Through direct interactions with thyroid receptors, an/or indirectly via up-stream signalling pathways, from the HPT axis (i.e., negative feedback regulation), malathion possess the ability to affect integrity of thyroidal follicular tissue, and it can also block or delay its hormonal functioning. This insecticide can alter the majority of the ontogenetic processes, inducing several deformities, and also provoking decreases in the growth and survival patterns. The present study has been performed to determine the sublethal effects of malathion during the first month of life of the Senegalese sole, Solea senegalensis, and it is mainly focused on the metamorphosis phase. Different transcript expression levels (i.e. thyroid receptors, matrix and bone -Gla-proteins) and immunohistochemical patterns (i.e. thyroid hormones, osteocalcin, cell proliferation) have been analysed during the most critical phases of the flatfish metamorphosis, that is, through differentiation of thyroid system and skeletal development, migration of the eye, and further adaptation to benthic behaviours.ResultsIn early life stages of the Senegalese sole, the exposure to the highest concentration of malathion (6.25 μg/L) affected to the growth patterns, showing the exposed individuals, a reduction around 60 and 92% of the total length and the dry weigth, respectively. In paralell, a significant reduction of the thyroid follicles (i.e., size and number) it was also been recorded, in a dose-dependent way. Abnormal phenotypes induced in the exposed larvae, did not complete the process of metamorphosis, and displayed several morphological abnormalities and developmental disorders, which were mainly associated with the eye migration process, and with thyroidal and skeletal disorders (i.e., transcriptional and protein changes of thyroid hormones and receptors, and of matrix and bone Gla proteins distribution), that conduced to an inadequate adaptation to the benthic life.ConclusionsIn the Senegalese sole, the majority of the ontogenetic alterations induced by the exposure to malathion were mainly associated to the metamorphosis period, which is a thyroid-driven proccess. In fact, most crucial and transitional ontogenic events, appeared notably disturbed, for e.g., thyroid gland differentiation and functioning, migration of eye, skeletal development and benthonic behaviors.

Dataset Information

Molecular characterization and expression analysis of five different elongation factor 1 alpha genes in the flatfish Senegalese sole (Solea senegalensis Kaup): differential gene expression and thyroid hormones dependence during metamorphosis.

Publications

Molecular characterization and expression analysis of five different elongation factor 1 alpha genes in the flatfish Senegalese sole (Solea senegalensis Kaup): differential gene expression and thyroid hormones dependence during metamorphosis.

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