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Scleraxis genes are required for normal musculoskeletal development and for rib growth and mineralization in zebrafish

Research output: Contribution to journalArticle

Original languageEnglish
Number of pages15
JournalFASEB Journal
Early online date17 May 2019
DateAccepted/In press - 15 Apr 2019
DateE-pub ahead of print (current) - 17 May 2019


Tendons are essential part of the musculoskeletal system connecting muscle and skeletal elements to enable force generation. The transcription factor Scleraxis marks vertebrate tendons from early specification. Scleraxis-null mice are viable and have a range of tendon and bone defects in trunk and limbs but no described cranial phenotype. We report the expression of zebrafish Scleraxis orthologues: scxa and scxb in cranial and intramuscular tendons and in other skeletal elements. Single mutants for either scxa or scxb, generated by CRISPR/Cas9, are viable and fertile as adult fish. Whereas scxb mutants show no obvious phenotype, scxa mutant embryos have defects in cranial tendon maturation and muscle misalignment. Mutation of both scleraxis genes results in more severe defects in cranial tendon differentiation, muscle and cartilage dysmorphogenesis and paralysis, and lethality by 2-5 weeks indicating an essential function for Scleraxis for craniofacial development. At juvenile and adult stages, ribs in scxa mutants fail to mineralize and/or are small and heavily fractured. Scxa mutants also have smaller muscle volume, abnormal swim movement and defects in bone growth and composition. Scleraxis function is therefore essential for normal craniofacial form and function and vital for fish development.

    Research areas

  • zebrafish, tendon, bone, ribs, muscle, swimming

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    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via FASEB at . Please refer to any applicable terms of use of the publisher.

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