Taurine homeostasis requires de novo synthesis via cysteine sulfinic acid decarboxylase during zebrafish early embryogenesis.
Cysteine sulfinic acid decarboxylase (Csad) is the rate-limiting enzyme in the de novo biosynthesis of taurine. There are a number of physiological roles of taurine, such as bile salt synthesis, osmoregulation, lipid metabolism, and oxidative stress inhibition. To investigate the role of de novo synthesis of taurine during embryonic development, zebrafish csad was cloned and functionally analyzed. Semi-quantitative RT-PCR showed that csad transcripts are maternally deposited, while whole-mount in situ hybridization demonstrated that csad is expressed in yolk syncytial layer and various embryonic tissues such as notochord, brain, retina, pronephric duct, liver, and pancreas. Knockdown of csad significantly reduced the embryonic taurine level, and the affected embryos had increased early mortality and cardiac anomalies. mRNA coinjection and taurine supplementation rescued the cardiac phenotypes suggesting that taurine originating from the de novo synthesis pathway plays a role in cardiac development. Our findings indicated that the de novo synthesis pathway via Csad plays a critical role in taurine homeostasis and cardiac development in zebrafish early embryos.
Department of Animal Science and Technology, National Taiwan University, Taipei 106, Taiwan.
Yen-Chia
YC
Chang
Shih-Torng
ST
Ding
Yen-Hua
YH
Lee
Ya-Ching
YC
Wang
Ming-Feng
MF
Huang
I-Hsuan
IH
Liu
D000818:Animals; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D008297:Male; D013654:Taurine / Q000096:biosynthesis*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*
D029941:Fish Proteins; D013654:Taurine; D002262:Carboxy-Lyases; C019972:sulfoalanine decarboxylase