Genome sequencing and analysis of black flounder (Paralichthys orbignyanus) reveals new insights into Pleuronectiformes genomic size and structure.

Black flounder (Paralichthys orbignyanus, Pleuronectiformes) is a commercially significant marine fish with promising aquaculture potential in Argentina. Despite extensive studies on Black flounder aquaculture, its limited genetic information available hampers the crucial role genetics plays in the development of this activity. In this study, we first employed Illumina sequencing technology to sequence the entire genome of Black flounder.

Overview and New Insights Into the Diversity, Evolution, Role, and Regulation of Kisspeptins and Their Receptors in Teleost Fish.

In the last two decades, kisspeptin (Kiss) has been identified as an important player in the regulation of reproduction and other physiological functions in vertebrates, including several fish species. To date, two ligands (Kiss1, Kiss2) and three kisspeptin receptors (Kissr1, Kissr2, Kissr3) have been identified in teleosts, likely due to whole-genome duplication and loss of genes that occurred early in teleost evolution. Recent results in zebrafish and medaka mutants have challenged the notion that the kisspeptin system is essential for reproduction in fish, in marked contrast to the situation in mammals.

Kisspeptin and GnRH interactions in the reproductive brain of teleosts.

It is well known that gonadotropin-releasing hormone (Gnrh) has a key role in reproduction by regulating the synthesis and release of gonadotropins from the anterior pituitary gland of all vertebrates. About 25 years ago, another neuropeptide, kisspeptin (Kiss1) was discovered as a metastasis suppressor of melanoma cell lines and then found to be essential for mammalian reproduction as a stimulator of hypothalamic Gnrh and regulator of puberty onset. Soon after, a kisspeptin receptor (kissr) was found in the teleost brain.

Kisspeptins and their receptors in the brain-pituitary-gonadal axis of Odonthestes bonariensis: Their relationship with gametogenesis along the reproductive cycle.

In vertebrates, the reproduction is controlled by the brain-pituitary-gonadal (BPG) axis and kisspeptin has emerged as a key player of this axis. In this study, we analyzed changes in the expression levels of kiss1, kiss2, and their receptors, kissr2 and kissr3 during gametogenesis in the BPG axis of feral Odontesthes bonariensis. In females, levels of brain kiss1 showed an increase at final maturation (Fm), while kiss2 levels were shown to be high at primary growth (Pg) stage, with no differences in the expression of their receptors.

Activity of etv5a and etv5b genes in the hypothalamus of fasted zebrafish is influenced by serotonin.

Serotonin has been implicated in the inhibition of food intake in vertebrates. However, the mechanisms through which serotonin acts has yet to be elucidated. Recently, ETV5 (ets variant gene 5) has been associated with obesity and food intake control mechanisms in mammals.

Kisspeptin system in pejerrey fish (Odontesthes bonariensis). Characterization and gene expression pattern during early developmental stages.

In vertebrates, kisspeptins and their receptors are known to be related to puberty onset and gonadal maturation, however, there are few studies concerning their role in early development. Here, we characterize the kisspeptin system in the pejerrey, Odontesthes bonariensis, a fish with strong temperature-dependent sex determination. We reconstructed the phylogenetic history of the two ligands (kiss1 and kiss 2) and two receptors (kissr2 and kissr3) in pejerrey in the context of recent classifications of bony fishes, determined their tissue distribution and documented the early expression pattern of these ligands and receptors.

Stage-specific gene expression during spermatogenesis in the Senegalese sole (Solea senegalensis), a fish with semi-cystic type of spermatogenesis, as assessed by laser capture microdissection and absolute quantitative PCR.

Spermatogenesis is a complex process where hormonal signals regulate the interaction of different cell types in a tight spatial and temporal fashion. The Senegalese sole (Solea senegalensis) is a marine flatfish that, in contrast to many fish, exhibits a semi-cystic, asynchronous pattern of spermatogenesis progression. This pattern is characterized by the release of spermatids into the tubule lumen, where they transform into spermatozoa.

The kisspeptin system genes in teleost fish, their structure and regulation, with particular attention to the situation in Pleuronectiformes.

It is well established that Kisspeptin regulates the onset of puberty in vertebrates through stimulation of the secretion of gonadotropin-releasing hormones. However, the function of kisspeptin in peripheral tissues and in other functions is still poorly understood. Recently, the evolution and distribution of kisspeptin genes in vertebrates has been clarified.

Using zebrafish transgenesis to test human genomic sequences for specific enhancer activity.

We detail an approach for the identification of human tissue-specific transcriptional enhancers involving three steps: delineation of search space around a locus or target gene, in silico identification and size definition of putative candidate sequences, and testing through several independent genomic insertions in a transgenic zebrafish reporter assay. Candidate sequences are defined through evolutionary conservation, transcription factor binding and chromatin marks (e.g.

Sex-specific changes in the expression of kisspeptin, kisspeptin receptor, gonadotropins and gonadotropin receptors in the Senegalese sole (Solea senegalensis) during a full reproductive cycle.

Kisspeptin is thought to have a major role in the control of the onset of puberty in vertebrates. However, our current understanding of its function in fish and how it integrates with other hormones is incomplete due to the high diversity of this group of animals and a still limited amount of available data. This study examined the temporal and spatial changes in expression of kisspeptin, gonadotropins and their respective receptors in the Senegalese sole during a full reproductive cycle.

Gene structure analysis of kisspeptin-2 (Kiss2) in the Senegalese sole (Solea senegalensis): characterization of two splice variants of Kiss2, and novel evidence for metabolic regulation of kisspeptin signaling in non-mammalian species.

Kisspeptin signaling in the brain is involved in the control of the onset of puberty in vertebrates. In this study, we present novel evidence indicating that kisspeptin may link energy balance and reproduction. For that purpose, we determined the complete gene structure of kisspeptin in a teleost fish, the Senegalese sole (Ss).

Gene structure of the Kiss1 receptor-2 (Kiss1r-2) in the Atlantic halibut: insights into the evolution and regulation of Kiss1r genes.

Kisspeptin and its receptor, Kiss1r, play an essential role in the control of the onset of puberty in vertebrates. We characterized the cDNA and genomic DNA encoding Kiss1r in Atlantic halibut (Hippoglossus hippoglossus). The 1146bp open reading frame predicts a 381 amino acid protein with high homology to the Kiss1r-2 of other teleost fish.

Identification of two isoforms of the Kisspeptin-1 receptor (kiss1r) generated by alternative splicing in a modern teleost, the Senegalese sole (Solea senegalensis).

The KISSPEPTIN-1 receptor (KISS1R) and its ligands (KISSPEPTINS) are implicated in the regulation of the onset of puberty. We report the coding region and genomic structure of the kiss1r gene of a modern teleost, the Senegalese sole (Ss). Ss kiss1r cDNA contained an opening frame of 1137 bp, which results in a predicted 378 amino acid protein.