All vertebrates have a definitive thyroid gland,or thyroid for short.As a critical organ for growth,development and metabolism,its origin and evolution have long received attention.On the basis of anatomical position,...All vertebrates have a definitive thyroid gland,or thyroid for short.As a critical organ for growth,development and metabolism,its origin and evolution have long received attention.On the basis of anatomical position,endodermal origination and histological features,the endostyle of amphioxus has been proposed as a homologue to the thyroid of vertebrates.This homology is further supported by the findings that the amphioxus endostyle abounds in thyroid hormones,possesses several thyroid-specific proteins such as thyroperoxidase,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase and thyroglobulin,and expresses the thyroid-related transcription factors involved in the regulation of development of the vertebrate thyroid,including Nkx2.1,FoxE4 and Pax2/5/8.Importantly,our study on functionality,together with others,indicates significant similarities between the amphioxus endostyle and the vertebrate thyroid gland.Moreover,we show that the production of thyroid hormones by the amphioxus endostyle is mediated in a fashion similar to that of the vertebrate thyroid.These provide solid evidences that the amphioxus endostyle is the homologue of the vertebrate thyroid.From a phylogenetic viewpoint,we propose that the hypobranchial ridge,or endostyle-like structure,of hemichordates is the most primitive forerunner of the thyroid,from which the vertebrate thyroid is formed through the transformation of non-follicular endostyle of amphioxus to follicular endocrine organ of vertebrates.We also raise a couple of questions that demand further study.展开更多
Pituitary gland,or pituitary for short,is characteristic of all vertebrates.As a“master gland”controlling a multitude of important functions in the body,its evolutionary origin has been an object of investigations o...Pituitary gland,or pituitary for short,is characteristic of all vertebrates.As a“master gland”controlling a multitude of important functions in the body,its evolutionary origin has been an object of investigations of evolutionary biology for two centuries.Previous morphological,ultrastructural and immunohistochemical studies suggested the homology of the Hatschek’s pit of amphioxus and vertebrate pituitary.Developmental genetics study showed that the development of Hatschek’s pit and vertebrate pituitary is both subject to regulation by the common genes such as Pit1,Lhx3 and BMP3b.Our recent studies demonstrated that the Hatschek’s pit is able to secrete growth hormone(GH)-like hormone and thyroid-stimulating hormone(TSH)-like hormone that both play functions similar to vertebrate GH and TSH.We thus think that the emergence of Hatschek’s pit represents one of important events during endocrine network evolution,which laid a foundation for the subsequent formation of a hypothalamic-pituitary system in vertebrates.展开更多
Liver is characteristic of all vertebrates.As a critical hub for many physiological processes including metabolism,innate immunity,protein synthesis and detoxification,its evolutionary origin was largely underapprecia...Liver is characteristic of all vertebrates.As a critical hub for many physiological processes including metabolism,innate immunity,protein synthesis and detoxification,its evolutionary origin was largely underappreciated in history,and only received due attention in recent decades.It has been suggested by morphological,ultrastructural and immunohistochemical studies that the hepatic caecum of amphioxus is homologous to the liver of vertebrate species.Molecular biology studies demonstrated that amphioxus hepatic caecum expresses plenty of vertebrate liver-specific genes.Our functional studies revealed significant similarities between amphioxus hepatic caecum and vertebrate liver.We also found that the functions of hepatic caecum are subjected to the regulation of pituitary hormones just as the liver does.These provide solid evidences supporting the notion that the hepatic caecum is the homologue of liver,which may represent the first stage in chordate evolution,laying a foundation for the subsequent formation of the liver as we know it in vertebrates.Further studies on the specification and morphogenesis of hepatic caecum in amphioxus will shed more lights on the origin and evolution of vertebrate liver.展开更多
基金The National Natural Science Foundation of China under contact No.32270434.
文摘All vertebrates have a definitive thyroid gland,or thyroid for short.As a critical organ for growth,development and metabolism,its origin and evolution have long received attention.On the basis of anatomical position,endodermal origination and histological features,the endostyle of amphioxus has been proposed as a homologue to the thyroid of vertebrates.This homology is further supported by the findings that the amphioxus endostyle abounds in thyroid hormones,possesses several thyroid-specific proteins such as thyroperoxidase,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase and thyroglobulin,and expresses the thyroid-related transcription factors involved in the regulation of development of the vertebrate thyroid,including Nkx2.1,FoxE4 and Pax2/5/8.Importantly,our study on functionality,together with others,indicates significant similarities between the amphioxus endostyle and the vertebrate thyroid gland.Moreover,we show that the production of thyroid hormones by the amphioxus endostyle is mediated in a fashion similar to that of the vertebrate thyroid.These provide solid evidences that the amphioxus endostyle is the homologue of the vertebrate thyroid.From a phylogenetic viewpoint,we propose that the hypobranchial ridge,or endostyle-like structure,of hemichordates is the most primitive forerunner of the thyroid,from which the vertebrate thyroid is formed through the transformation of non-follicular endostyle of amphioxus to follicular endocrine organ of vertebrates.We also raise a couple of questions that demand further study.
基金The National Natural Science Foundation of China under contract No.32073000the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2018SDKJ0302-1.
文摘Pituitary gland,or pituitary for short,is characteristic of all vertebrates.As a“master gland”controlling a multitude of important functions in the body,its evolutionary origin has been an object of investigations of evolutionary biology for two centuries.Previous morphological,ultrastructural and immunohistochemical studies suggested the homology of the Hatschek’s pit of amphioxus and vertebrate pituitary.Developmental genetics study showed that the development of Hatschek’s pit and vertebrate pituitary is both subject to regulation by the common genes such as Pit1,Lhx3 and BMP3b.Our recent studies demonstrated that the Hatschek’s pit is able to secrete growth hormone(GH)-like hormone and thyroid-stimulating hormone(TSH)-like hormone that both play functions similar to vertebrate GH and TSH.We thus think that the emergence of Hatschek’s pit represents one of important events during endocrine network evolution,which laid a foundation for the subsequent formation of a hypothalamic-pituitary system in vertebrates.
基金The National Natural Science Foundation of China under contract No.32270434。
文摘Liver is characteristic of all vertebrates.As a critical hub for many physiological processes including metabolism,innate immunity,protein synthesis and detoxification,its evolutionary origin was largely underappreciated in history,and only received due attention in recent decades.It has been suggested by morphological,ultrastructural and immunohistochemical studies that the hepatic caecum of amphioxus is homologous to the liver of vertebrate species.Molecular biology studies demonstrated that amphioxus hepatic caecum expresses plenty of vertebrate liver-specific genes.Our functional studies revealed significant similarities between amphioxus hepatic caecum and vertebrate liver.We also found that the functions of hepatic caecum are subjected to the regulation of pituitary hormones just as the liver does.These provide solid evidences supporting the notion that the hepatic caecum is the homologue of liver,which may represent the first stage in chordate evolution,laying a foundation for the subsequent formation of the liver as we know it in vertebrates.Further studies on the specification and morphogenesis of hepatic caecum in amphioxus will shed more lights on the origin and evolution of vertebrate liver.
