Xi J, Yue J, Yang Z
Department of Pharmacy, Wuhan University of Science and Technology School of Medicine, Hubei, China.
Department of Pharmacology, Wuhan University School of Basic Medical Science, Hubei, China.
Genet Mol Res. 2015 Apr 27;14(2):3948-56. doi: 10.4238/2015.April.27.9.
Retinoic acid (RA) plays a crucial role in cellular proliferation, differentiation, and apoptosis. The physiological activity of RA begins early in development and continues throughout an organism's life. RA distribution is tightly controlled by the RA synthetases ALDH1As and the metabolic enzymes CYP26s. We analyzed the expressions of ALDH1As and CYP26s in whole embryos during zebrafish (Danio rerio) development and in adult zebrafish organs, by quantitative reverse transcriptase polymerase chain reaction analysis. All the ALDH1A and CYP26 genes exhibited similar pulse expression patterns, with peak expressions at different developmental stages. ALDH1A2 exhibited an earlier and sharper expression peak [12 hours post-fertilization (hpf)] than ALDH1A3 (24 hpf). CYP26A1 transcription peaked earlier (8 hpf) than CYP26B1 and CYP26C1 (12 hpf), while CYP26C1 expression dropped to basal levels later (48 hpf) than that of CYP26A1 and CYP26B1 (18 hpf). ALDH1A2 and CYP26A1 exhibited the highest mRNA peak level and seem to be the dominant isoenzymes in their families during zebrafish development. Expression patterns of ALDH1As and CYP26s in most adult zebrafish tissues were similar to those in humans. Nevertheless, three CYP26s were more vigorously expressed in the zebrafish brain than in human organs, whereas much weaker ALDH1A and CYP26 transcription was found in the zebrafish liver and intestine. This suggests that RA metabolic rates differ between zebrafish and humans or that other enzymes are responsible for RA homeostasis in the zebrafish liver and intestine. All the ALDH1A and CYP26 genes exhibited distinct expression patterns during zebrafish development and in adult zebrafish tissues.
视黄酸（RA）在细胞增殖、分化和凋亡过程中发挥着关键作用。RA的生理活性在发育早期就已开始，并在生物体的整个生命过程中持续存在。RA的分布受到RA合成酶ALDH1As和代谢酶CYP26s的严格控制。我们通过定量逆转录聚合酶链反应分析，研究了斑马鱼（Danio rerio）发育过程中全胚胎以及成年斑马鱼器官中ALDH1As和CYP26s的表达情况。所有的ALDH1A和CYP26基因都呈现出相似的脉冲式表达模式，在不同发育阶段达到表达峰值。与ALDH1A3（受精后24小时，hpf）相比，ALDH1A2表现出更早且更明显的表达峰值（受精后12小时，hpf）。CYP26A1的转录峰值（8 hpf）比CYP26B1和CYP26C1（12 hpf）出现得更早，而CYP26C1的表达水平降至基础水平的时间（48 hpf）比CYP26A1和CYP26B1（18 hpf）更晚。ALDH1A2和CYP26A1呈现出最高的mRNA峰值水平，并且在斑马鱼发育过程中似乎是其家族中的主要同工酶。大多数成年斑马鱼组织中ALDH1As和CYP26s的表达模式与人类相似。然而，三种CYP26s在斑马鱼大脑中的表达比在人类器官中更为活跃，而在斑马鱼肝脏和肠道中，ALDH1A和CYP26的转录则要弱得多。这表明斑马鱼和人类之间的RA代谢率存在差异，或者其他酶在斑马鱼肝脏和肠道中负责RA的稳态平衡。所有的ALDH1A和CYP26基因在斑马鱼发育过程中和成年斑马鱼组织中都呈现出独特的表达模式。
