The function of pregneolone and progesterone in early development of zebrafish

• Main Authors: Cheng-Yi Lin, 林政毅
• Other Authors: Bon-Chu Chung
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/16678374036518342944

碩士 === 國立陽明大學 === 生化暨分子生物研究所 === 95 === Steroids hormones are important small molecules that maintain body salt and energy balance, sex identity, and neuron survival. cyp11a1 and hsd3b are the first and second enzymes in the steroidogenic pathway, respectively, that convert cholesterol into pregnenolone (P5) and then progesterone (P4). Blocking cyp11a1 expression results in impaired epiboly, convergence, and extension movement and disrupting hsd3b leads to expanded dorsal tissues in zebrafish embryos, yet little is known about the function of P5 and P4 in early developmental stages. Here, I studied the role of P5 and P4 by blocking cyp11a1 and hsd3b expression with antisense morpholino injection. Reducing cyp11a1 expression resulted in expanded ventral domain and reduced dorsal domain during gastrulation, although the embryos appeared normal at the late blastula stage. This ventralized defect was rescued by introducing cyp11a1 mRNA. Although disrupting cyp11a1 expression led to low P5 amount, P4 level was not changed in these cyp11a1 deficient embryos. I further found that embryos treated with P5 promote epiboly movement, but P4 treatment delayed it. Furthermore, cyp11a1 and hsd3b antagonize to each other in the activity to expand the dorsal domain. Since the altered dorsal-ventral domain was started at early gastrulation and became more obvious at the late gastrulation stage, P5 and P4 both may affect cell fate maintenance through regulating cell migration during gastrulation period. Convergence movement is the dorsal migration of lateral cell. Thus, dorsal tissues are reduced when lateral cells failed to reach the dorsal region in convergence deficient embryos. Therefore, the defect of convergence movement may affect cell determination during gastrulation in cyp11a1 deficient embryos.