Intermuscular bones(IBs)are slender linear bones embedded in muscle,which ossify from tendons through a process of intramembranous ossification,and only exist in basal teleosts.IBs are essential for fish swimming,but ...Intermuscular bones(IBs)are slender linear bones embedded in muscle,which ossify from tendons through a process of intramembranous ossification,and only exist in basal teleosts.IBs are essential for fish swimming,but they present a choking risk during human consumption,especially in children,which can lead to commercial risks that have a negative impact on the aquaculture of these fish.In this review,we discuss the morphogenesis and functions of IBs,including their underlying molecular mechanisms,as well as the advantages and disadvantages of different methods for IB studies and techniques for breeding and generating IB-free fish lines.This review reveals that the many key genes involved in tendon development,osteoblast differentiation,and bone formation,e.g.,scxa,msxC,sost,twist,bmps,and osterix,also play roles in IB development.Thus,this paper provides useful information for the breeding of new fish strains without IBs via genome editing and artificial selection.展开更多
Intermuscular bones(IBs)are ossified from tendons and only occur in lower teleosts.Positive association between the regulation of scleraxis gene(scx)and tendon development gave us reasons to speculate that the scx gen...Intermuscular bones(IBs)are ossified from tendons and only occur in lower teleosts.Positive association between the regulation of scleraxis gene(scx)and tendon development gave us reasons to speculate that the scx gene may play a potential role in regulating the development of IBs.A phylogenetic analysis conducted for this study revealed potential functional differentiation between two scx orthologues,scxa and scxb.The scxa^(-/-) and scxb^(-/-) zebrafish were generated through CRISPR-Cas9 technology to study the role of scx in the IB and rib development.The results showed a significant reduction of the number of IBs in adult scxa-1^(-/-) zebrafish,with almost 70%reduction(15-25 IBs)compared to the wild type scxa-1^(+/+)zebrafish(76-80 IBs).In the scxa-1^(+/+)adults,IBs were observed in both dorsal and tail segments;however,in scxa-1^(-/-)fish IBs were observed only in the tail segment(none in the dorsal segment).Although scxa-1^(-/-) zebrafish had rib defects,the mutants were viable and fertile as adult fish.The scxb^(-/-) zebrafish had the same number of IBs and same skeletal phenotype as the wild-type fish.This suggests that only scxa has a crucial role in the IB development,and confirms functional differentiation of scx orthologues.To further clarify the molecular mechanism by which scxa affects the IB development,we conducted comparative transcriptome analysis of dorsal tissue samples of scxa-1^(+/+)(with IBs)and scxa-1^(-/-) (without IBs),and further verified the expression of key genes via qPCR.This is the first study to identify a gene that controls the amount of IBs in fish,and it provides a new sight into the effects of scxa on the molecular mechanism of IB development in fish.展开更多
We documented the number, morphology, and distribution of intermuscular bones in five fishes of different ploidy： Carassius auratus （Abbr.WCC, 2n=100）, Carassius auratus variety PengZe （Abbr.PZCC, 3n=150）, improv...We documented the number, morphology, and distribution of intermuscular bones in five fishes of different ploidy： Carassius auratus （Abbr.WCC, 2n=100）, Carassius auratus variety PengZe （Abbr.PZCC, 3n=150）, improved triploid crucian carp （Abbr.ITCC, 3n=150）, improved red crucian carp （Carassius auratus red var., Abbr.IRCC, , 2n=100）, and improved allotet- raploids （Abbr.GAT, （, 4n=200）. The number of intermuscular bones in WCC, PZCC, and GxAT ranged from 78 to 83 （n =81）, 80 to 86 （n =84）, and 77 to 84 （n=82）, respectively. The numbers in ITCC and IRCC were significantly lower, ranging from 77 to 82 （ n =79） and 58 to 77 （ n =71）, respectively. The average number of intermuscular bones in each sarco- mere, ranked in order from highest to lowest, was 0.721 （WCC）, 0.673 （PZCC）, 0.653 （GAT）, 0.633 （ITCC）, and 0.608 （IRCC）. There was no difference between ITCC and GxAT or between GxAT and PZCC. However, the average number of intermuscular bones in the sarcomeres of ITCC, WCC, and PZCC differed significantly, as did that of IRCC and the four other kinds of fish. The intermuscular bone of these five fishes was divided into seven shape categories, non-forked （I）, one-end-unequal-bi-fork （）, one-end-equal-bi-fork （Y）, one-end-multi-fork, two-end-bi-fork, two-end-multi-fork, and tree- branch types. Generally, the morphological complexity was higher in the anterior intermuscular bones than in the posterior body. The number of intermuscular bones was similar but not equal between the left and right sides of the body. ITCC had sig- nificantly fewer intermuscular bones than either WCC or PZCC, making it of greater commercial value. Additionally, IRCC and ITCC had fewer intermuscular bones than WCC. Our observations are significant in both fish bone developmental biology and genetic breeding.展开更多
基金This work was supported by the National Natural Science Foundation of China(U1702233 and U1902202)Program of the Chinese Academy of Sciences(XDA24030505 and XDA23080502)Program of Yunnan Provincial Science and Technology Department(202003AD150017 and 2018FY001-007)。
文摘Intermuscular bones(IBs)are slender linear bones embedded in muscle,which ossify from tendons through a process of intramembranous ossification,and only exist in basal teleosts.IBs are essential for fish swimming,but they present a choking risk during human consumption,especially in children,which can lead to commercial risks that have a negative impact on the aquaculture of these fish.In this review,we discuss the morphogenesis and functions of IBs,including their underlying molecular mechanisms,as well as the advantages and disadvantages of different methods for IB studies and techniques for breeding and generating IB-free fish lines.This review reveals that the many key genes involved in tendon development,osteoblast differentiation,and bone formation,e.g.,scxa,msxC,sost,twist,bmps,and osterix,also play roles in IB development.Thus,this paper provides useful information for the breeding of new fish strains without IBs via genome editing and artificial selection.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.31872559)National Key Research and Development Program(Grant No.2018YFD0900102)+2 种基金Modern Agriculture Industry Technology System Construction Projects of China titled as-Staple Freshwater Fishes Industry Technology System(Grant No.CARS-46-08)Fundamental Research Funds for the Central Universities(Grant No.2662018PY035)State Key Laboratory of Developmental Biology of Freshwater Fish(2018KF003).
文摘Intermuscular bones(IBs)are ossified from tendons and only occur in lower teleosts.Positive association between the regulation of scleraxis gene(scx)and tendon development gave us reasons to speculate that the scx gene may play a potential role in regulating the development of IBs.A phylogenetic analysis conducted for this study revealed potential functional differentiation between two scx orthologues,scxa and scxb.The scxa^(-/-) and scxb^(-/-) zebrafish were generated through CRISPR-Cas9 technology to study the role of scx in the IB and rib development.The results showed a significant reduction of the number of IBs in adult scxa-1^(-/-) zebrafish,with almost 70%reduction(15-25 IBs)compared to the wild type scxa-1^(+/+)zebrafish(76-80 IBs).In the scxa-1^(+/+)adults,IBs were observed in both dorsal and tail segments;however,in scxa-1^(-/-)fish IBs were observed only in the tail segment(none in the dorsal segment).Although scxa-1^(-/-) zebrafish had rib defects,the mutants were viable and fertile as adult fish.The scxb^(-/-) zebrafish had the same number of IBs and same skeletal phenotype as the wild-type fish.This suggests that only scxa has a crucial role in the IB development,and confirms functional differentiation of scx orthologues.To further clarify the molecular mechanism by which scxa affects the IB development,we conducted comparative transcriptome analysis of dorsal tissue samples of scxa-1^(+/+)(with IBs)and scxa-1^(-/-) (without IBs),and further verified the expression of key genes via qPCR.This is the first study to identify a gene that controls the amount of IBs in fish,and it provides a new sight into the effects of scxa on the molecular mechanism of IB development in fish.
基金supported by Special Fund for Agro-scientific Research in the Public Interest (200903046)the National Natural Science Foundation of China (30930071)+5 种基金Major International Cooperation Projects of the National Natural Science Foundation of China (31210103918)Innovative Research Groups of Hunan Provincial Natural Science Fund (10JJ7004)the National High Technology Research and Development Program of China (2011AA100403)Pre-project of the National Key Basic Research and Development Program (2012CB722305)the Construct Program of the Key Discipline in Hunan ProvinceConstruct Program of the National Key Discipline
文摘We documented the number, morphology, and distribution of intermuscular bones in five fishes of different ploidy： Carassius auratus （Abbr.WCC, 2n=100）, Carassius auratus variety PengZe （Abbr.PZCC, 3n=150）, improved triploid crucian carp （Abbr.ITCC, 3n=150）, improved red crucian carp （Carassius auratus red var., Abbr.IRCC, , 2n=100）, and improved allotet- raploids （Abbr.GAT, （, 4n=200）. The number of intermuscular bones in WCC, PZCC, and GxAT ranged from 78 to 83 （n =81）, 80 to 86 （n =84）, and 77 to 84 （n=82）, respectively. The numbers in ITCC and IRCC were significantly lower, ranging from 77 to 82 （ n =79） and 58 to 77 （ n =71）, respectively. The average number of intermuscular bones in each sarco- mere, ranked in order from highest to lowest, was 0.721 （WCC）, 0.673 （PZCC）, 0.653 （GAT）, 0.633 （ITCC）, and 0.608 （IRCC）. There was no difference between ITCC and GxAT or between GxAT and PZCC. However, the average number of intermuscular bones in the sarcomeres of ITCC, WCC, and PZCC differed significantly, as did that of IRCC and the four other kinds of fish. The intermuscular bone of these five fishes was divided into seven shape categories, non-forked （I）, one-end-unequal-bi-fork （）, one-end-equal-bi-fork （Y）, one-end-multi-fork, two-end-bi-fork, two-end-multi-fork, and tree- branch types. Generally, the morphological complexity was higher in the anterior intermuscular bones than in the posterior body. The number of intermuscular bones was similar but not equal between the left and right sides of the body. ITCC had sig- nificantly fewer intermuscular bones than either WCC or PZCC, making it of greater commercial value. Additionally, IRCC and ITCC had fewer intermuscular bones than WCC. Our observations are significant in both fish bone developmental biology and genetic breeding.
