Zebrafish as a vertebrate model of ENOSF1 function

The human enolase superfamily member 1 (ENOSF1) gene encodes a protein involved in S‐adenosylmethionine (AdoMet) metabolism. This study used the zebrafish ( Danio rerio ) as a vertebrate model of ENOSF1 function during development. Whole mount in situ hybridization (WISH) showed that zebrafish ENOSF1 (drENOSF1) is zygotic and expressed ubiquitously through 24 hours post fertilization (hpf). After 24 hours, drENOSF1 is restricted to notochord. Embryos injected with drENOSF1‐EGFP mRNA grew slower than EGFP mRNA‐injected embryos. Injection of a morpholino targeting the second ATG (ATG2) in endogenous drENOSF1 resulted in embryos with kinked notochords, shortened anterior‐posterior axes, and circulatory edema. Injection of a morpholino targeting splicing of exon 10 (e10i10) resulted in embryos with a less severe phenotype. RT‐PCR shows that e10i10‐injected embryos expressed a large proportion of misspliced drENOSF1 transcript. WISH for tissue‐specific gene expression showed that embryos injected with both morpholinos have deformed notochord and pronephros. TUNEL staining revealed increased apoptosis in the peri‐notochord region. TUNEL results are mirrored in WISH for two enzymes needed to synthesize AdoMet: MATIIA expression increases in ATG2‐injected embryos, while MATIIB expression decreased. This study represents the first report of phenotypes associated with animal ENOSF1 knockdown in vivo . Grant Funding Source: NIH