title: Dihydrofolate reductase is required for the development of heart and outflow tract in zebrafish.
abstract: Folic acid is very important for embryonic development and folic acid inhibition can cause congenital heart defects in vertebrates. Dihydrofolate reductase (DHFR) is a key enzyme in folate-mediated metabolism. The dysfunction of DHFR disrupts the key biological processes which folic acid participates in. DHFR gene is conserved during vertebrate evolution. It is important to investigate the roles of DHFR in cardiac developments. In this study, we showed that DHFR knockdown resulted in the abnormal developments of zebrafish embryos in the early stages. Obvious malformations in heart and outflow tract (OFT) were also observed in DHFR knockdown embryos. DHFR overexpression rescued the abnormal phenotypes in the DHFR knockdown group. DHFR knockdown had negative impacts on the expressions of NKX2.5 (NK2 transcription factor-related 5), MEF2C (myocyte-specific enhancer factor 2C), TBX20 (T-box 20), and TBX1 (T-box 1) which are important transcriptional factors during cardiac development process, while DHFR overexpression had positive effects. DHFR was required for Hedgehog pathway. DHFR knockdown caused reduced cell proliferation and increased apoptosis, while its overexpression promoted cell proliferation and inhibited apoptosis. Taken together, our study suggested that DHFR plays crucial roles in the development of heart and OFT in zebrafish by regulating gene transcriptions and affecting cell proliferation and apoptosis.
authors: Children's Hospital, Fudan University, Shanghai, China.
authors: Shuna
authors: S
authors: Sun
authors: Yonghao
authors: Y
authors: Gui
authors: Qiu
authors: Q
authors: Jiang
authors: Houyan
authors: H
authors: Song
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D055785:Gene Knockdown Techniques; D006321:Heart / Q000187:drug effects / Q000196:embryology* / Q000254:growth & development*; D006330:Heart Defects, Congenital / Q000378:metabolism; D000072576:Homeobox Protein Nkx-2.5; D008845:Microinjections; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000187:drug effects / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000187:drug effects / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000008:administration & dosage / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000187:drug effects / Q000378:metabolism
chemical_list: D000072576:Homeobox Protein Nkx-2.5; C559872:Mef2cb protein, zebrafish; D009124:Muscle Proteins; C528182:Nkx2.5 protein, zebrafish; D020825:T-Box Domain Proteins; C420984:TBX20 protein, human; D014157:Transcription Factors; D029961:Zebrafish Proteins; D013762:Tetrahydrofolate Dehydrogenase