Project description:At higher latitudes, vertebrates exhibit a seasonal cycle of reproduction in response to changes in day-length, referred to as photoperiodism. Extended day-length induces thyroid-stimulating hormone in the pars tuberalis of the pituitary gland. This hormone triggers the local activation of thyroid hormone in the mediobasal hypothalamus and eventually induces gonadal development. In avian species, light information associated with day-length is detected through photoreceptors located in deep-brain regions. Within these regions, the expressions of multiple photoreceptive molecules, opsins, have been observed. However, even though the Japanese quail is an excellent model for photoperiodism because of its robust and significant seasonal responses in reproduction, a comprehensive understanding of photoreceptors in the quail brain remains undeveloped. In this study, we initially analyzed an action spectrum using photoperiodically induced expression of the beta subunit genes of thyroid-stimulating hormone in quail. Among seven wavelengths examined, we detected maximum sensitivity of the action spectrum at 500 nm. The low value for goodness of fit in the alignment with a template of retinal1-based photopigment, assuming a spectrum associated with a single opsin, proposed the possible involvement of multiple opsins rather than a single opsin. Analysis of gene expression in the septal region and hypothalamus, regions hypothesized to be photosensitive in quail, revealed mRNA expression of a mammal-like melanopsin in the infundibular nucleus within the mediobasal hypothalamus. However, no significant diurnal changes were observed for genes in the infundibular nucleus. Xenopus-like melanopsin, a further isoform of melanopsin in birds, was detected in neither the septal region nor the infundibular nucleus. These results suggest that the mammal-like melanopsin expressed in the infundibular nucleus within the mediobasal hypothalamus could be candidate deep-brain photoreceptive molecule in Japanese quail. Investigation of the functional involvement of mammal-like melanopsin-expressing cells in photoperiodism will be required for further conclusions.

Project description:Japanese quail (Coturnix coturnix japonica) reach sexual maturity early, breed rapidly and successfully, and cost less and require less space than other birds raised for their meat and eggs. Given the value of this species for commercial production and experimental use as well as recent increasing demand, more studies are necessary to determine chromosomal regions and genes associated with gender and breed-differentiation in the species. Identification of sex-related genes can help target chromosomal regions for molecular sexing purposes. This study employed Trinity and edgeR for transcriptome analysis of next-generation RNA-seq data, which included 4 tissues obtained from 3 different breeds of Japanese quail (wild, miniature, and jumbo). The initial goal was to identify genes related to sexual dimorphism, as well as potential novel candidate genes for molecular sexing. Analysis and interpretation of differentially expressed genes shared between female and male tissue contrast groups provided insight into sex-related differences. Several of the genes identified in the present study as significant sex-related genes have been previously found in avian gene expression analyses (e.g. NIPBL, UBAP2), and other genes found differentially expressed in this study and not previously associated with sex-related differences may be considered potential candidates for molecular sexing (e.g. TERA, MYP0, PPR17, CASQ2). Additionally, other genes likely associated with neuronal and brain development (e.g. CHKA, NYAP), as well as body development and size differentiation (e.g. ANKRD26, GRP87) in quail were identified. Expression of homeobox protein regulating genes in the sex-related contrast group revealed two genes (HXC4, ISL1) that may regulate sex-specific anatomical development. Results of these analyses expand the currently limited pool of knowledge on the genetic features of the quail breed and could allow for more effective molecular sexing as well as selective breeding for traits important in commercial production.

Project description:Japanese quail (Coturnix coturnix japonica) reach sexual maturity early, breed rapidly and successfully, and cost less and require less space than other birds raised for their meat and eggs. Given the value of this species for commercial production and experimental use as well as recent increasing demand, more studies are necessary to determine chromosomal regions and genes associated with gender and breed-differentiation in the species. Identification of sex-related genes can help target chromosomal regions for molecular sexing purposes. This study employed Trinity and edgeR for transcriptome analysis of next-generation RNA-seq data, which included 4 tissues obtained from 3 different breeds of Japanese quail (wild, miniature, and jumbo). The initial goal was to identify genes related to sexual dimorphism, as well as potential novel candidate genes for molecular sexing. Analysis and interpretation of differentially expressed genes shared between female and male tissue contrast groups provided insight into sex-related differences. Several of the genes identified in the present study as significant sex-related genes have been previously found in avian gene expression analyses (e.g. NIPBL, UBAP2), and other genes found differentially expressed in this study and not previously associated with sex-related differences may be considered potential candidates for molecular sexing (e.g. TERA, MYP0, PPR17, CASQ2). Additionally, other genes likely associated with neuronal and brain development (e.g. CHKA, NYAP), as well as body development and size differentiation (e.g. ANKRD26, GRP87) in quail were identified. Expression of homeobox protein regulating genes in the sex-related contrast group revealed two genes (HXC4, ISL1) that may regulate sex-specific anatomical development. Results of these analyses expand the currently limited pool of knowledge on the genetic features of the quail breed and could allow for more effective molecular sexing as well as selective breeding for traits important in commercial production. This study employed Trinity and edgeR for transcriptome analysis of next-generation RNA-seq data, which included 4 tissues obtained from 3 different breeds of Japanese quail (wild, miniature, and jumbo).

Project description:Reproductive failure associated with heat stress is a well-known phenomenon in poultry. High temperatures also induce various metabolic disturbances in many animals. Because the liver plays a central role in metabolism, the present study aimed to clarify the relationship between liver and reproduction in Japanese quails exposed to high temperatures. In the consecutive 20-D experimental period, quails were treated with 25°C (control) or 34°C (heat) from 12:00 to 16:00. Eggs were collected for hatching. On completion of the experimental period, quails were humanely euthanized for hormone analyses (e.g., serum and ovarian follicles). Serum metabolites were analyzed using GC/MS. Liver and ovary samples were collected for mRNA levels, histomorphology, and metabolic analysis. Ovary and oviduct weights significantly decreased after daily heat exposure. The number and weight of hierarchical follicles also decreased. Consequently, egg weight decreased. Although there was no difference in fertilization rate, chick birth weight significantly decreased in the heated group. Corticosterone and 17?-estradiol in the serum significantly increased in the heated group. Yolk corticosterone and 17?-estradiol concentration and content were higher in the heated group. Ovary sterologenic enzymes gene P450scc and estrogen receptor expression level increased. The FSH receptor decreased in heat-stressed quails. MetaboAnalyst analysis indicated that high temperature affects propanoate metabolism, beta-alanine metabolism, aspartate metabolism, and histidine metabolism. Triglyceride and cholesterol levels in the liver increased in the heated group. The heated group also had an increased mRNA expression of AGPAT5, apoptosis gene caspase3, and the immunocytokine genes IL-6 and TLR4. However, NF-?B gene expression decreased. These results suggest that high temperatures affect lipid metabolism and apoptosis and cause inflammation in the liver. High temperature induced ovarian dysfunction, which resulted in the decline of hierarchical follicle number and weight, egg weight, and chick birth weight. The increased level of 17?-estradiol suggests liver damage. Protecting liver function from damage may assist quails cope in summer.

Dataset Information

Expression profiling of sexually dimorphic genes in the Japanese quail, Coturnix japonica.

Publications

Expression profiling of sexually dimorphic genes in the Japanese quail, Coturnix japonica.

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