Although most fishes are ectothermic,some,including tuna and billfish,achieve endothermy through specialized heat producing tissues that are modified muscles.How these heat producing tissues evolved,and whether they s...Although most fishes are ectothermic,some,including tuna and billfish,achieve endothermy through specialized heat producing tissues that are modified muscles.How these heat producing tissues evolved,and whether they share convergent molecular mechanisms,remain unresolved.Here,we generated a high-quality genome from the mackerel tuna(Euthynnus affinis)and investigated the heat producing tissues of this fish by single-nucleus and bulk RNA sequencing.Compared with other teleosts,tuna-specific genetic variation is strongly associated with muscle differentiation.Single-nucleus RNA-seq revealed a high proportion of specific slow skeletal muscle cell subtypes in the heat producing tissues of tuna.Marker genes of this cell subtype are associated with the relative sliding of actin and myosin,suggesting that tuna endothermy is mainly based on shivering thermogenesis.In contrast,cross-species transcriptome analysis indicated that endothermy in billfish relies mainly on nonshivering thermogenesis.Nevertheless,the heat producing tissues of the different species do share some tissue-specific genes,including vascular-related and mitochondrial genes.Overall,although tunas and billfishes differ in their thermogenic strategies,they share similar expression patterns in some respects,highlighting the complexity of convergent evolution.展开更多
Cardiac regeneration is an ancestral trait in vertebrates that is lost both as more recent vertebrate lineages evolved to adapt to new environments and selective pressures,and as members of certain species development...Cardiac regeneration is an ancestral trait in vertebrates that is lost both as more recent vertebrate lineages evolved to adapt to new environments and selective pressures,and as members of certain species developmentally progress towards their adult forms.While higher vertebrates like humans and rodents resolve cardiac injury with permanent fibrosis and loss of cardiac output as adults,neonates of these same species can fully regenerate heart structure and function after injury–as can adult lower vertebrates like many teleost fish and urodele amphibians.Recent research has elucidated several broad factors hypothesized to contribute to this loss of cardiac regenerative potential both evolutionarily and developmentally:an oxygen-rich environment,vertebrate thermogenesis,a complex adaptive immune system,and cancer risk trade-offs.In this review,we discuss the evidence for these hypotheses as well as the cellular participators and molecular regulators by which they act to govern heart regeneration in vertebrates.展开更多
基金supported by the National Natural Science Foundation of China(32122021)the National Key Research and Development Program of China(2022YFC3400300)+1 种基金the 1000 Talent Project of Shaanxi Province to Q.Q.and K.W.,the Fundamental Research Funds of Northwestern Polytechnic Universitythe Open Foundation from Marine Sciences in the First-Class Subjects of Zhejiang(OFMS011)。
文摘Although most fishes are ectothermic,some,including tuna and billfish,achieve endothermy through specialized heat producing tissues that are modified muscles.How these heat producing tissues evolved,and whether they share convergent molecular mechanisms,remain unresolved.Here,we generated a high-quality genome from the mackerel tuna(Euthynnus affinis)and investigated the heat producing tissues of this fish by single-nucleus and bulk RNA sequencing.Compared with other teleosts,tuna-specific genetic variation is strongly associated with muscle differentiation.Single-nucleus RNA-seq revealed a high proportion of specific slow skeletal muscle cell subtypes in the heat producing tissues of tuna.Marker genes of this cell subtype are associated with the relative sliding of actin and myosin,suggesting that tuna endothermy is mainly based on shivering thermogenesis.In contrast,cross-species transcriptome analysis indicated that endothermy in billfish relies mainly on nonshivering thermogenesis.Nevertheless,the heat producing tissues of the different species do share some tissue-specific genes,including vascular-related and mitochondrial genes.Overall,although tunas and billfishes differ in their thermogenic strategies,they share similar expression patterns in some respects,highlighting the complexity of convergent evolution.
基金This research was made possible by NIH F31 Fellowship(S.C.),NIH(R01HL138456)Department of Defense(W81XWH1910206)Program for Breakthrough Biomedical Research,and UCSF Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research Seed Grant(G.N.H.).
文摘Cardiac regeneration is an ancestral trait in vertebrates that is lost both as more recent vertebrate lineages evolved to adapt to new environments and selective pressures,and as members of certain species developmentally progress towards their adult forms.While higher vertebrates like humans and rodents resolve cardiac injury with permanent fibrosis and loss of cardiac output as adults,neonates of these same species can fully regenerate heart structure and function after injury–as can adult lower vertebrates like many teleost fish and urodele amphibians.Recent research has elucidated several broad factors hypothesized to contribute to this loss of cardiac regenerative potential both evolutionarily and developmentally:an oxygen-rich environment,vertebrate thermogenesis,a complex adaptive immune system,and cancer risk trade-offs.In this review,we discuss the evidence for these hypotheses as well as the cellular participators and molecular regulators by which they act to govern heart regeneration in vertebrates.
