斜带石斑鱼sox3基因cDNA的克隆及其时空表达特征分析

Studies on cDNA Cloning and Temporal and Spatial Expression of sox3 Gene in Grouper Epinephelus coioides

采用RACE-PCR方法从斜带石斑鱼的下丘脑SMART cDNA中克隆sox3基因,并研究其时空表达模式。研究结果表明,sox3 cDNA片段全长1152bp,共编码300个氨基酸。该基因在未受精卵和桑椹胚期仅可检测到微弱的转录本,从高囊胚期开始转录,一直到鱼苗1天,都维持着较高的表达水平。在肝和肾等6种组织中均检测不到转录本的存在,而在包括垂体和下丘脑等6种脑组织中可检测到不同强弱的转录本,呈现出很强的中枢神经系统的表达特异性。在未成熟卵巢中可检测到大量转录本的存在,在成熟卵子中可检测到微弱的转录本,而在处于变性期的性腺中检测不到转录本的存在,呈现出很强的雌性性腺特异性。由此我们推断,sox3基因在石斑鱼的中枢神经系统发育和卵子发生过程中起了重要作用。

The Epinephelus coioides sox3 cDNA was cloned from the SMART cDNAs of Epinephelus coioides hy-pothalamus by RACE-PCR, and the temporal and spatial expression patterns were analyzed by RT-PCR. The sox3 cDNA contains 1152 bp and encodes 300 arnino acids (aa). Its slight maternal mRNA could be detected from unfertilized eggs to morula stage, but the transcripts had appeared from high-blastoderm stage during embryonic development,and maintained a considerable high level till the one day's fry. No sox3 transcripts were found in liver, kidney, spleen, fat, heart and muscle, but unequal amount of sox3 transcripts can be detected in six kinds of brain tissues, such as pituitary, hypothalamus, telencephalon, cerebellum, midbrain and medulla oblongata, which suggests that sox3 expression is specific in central nervous system (CNS). In addition, we also found the abundant transcripts in immature ovary, slight transcripts in mature eggs, and no transcripts in the gonad of sex reversal period. The data reveal the sox3 expression specificity for female gonad. Based on these results , we suggest that sox3 should play a key role in CNS development and oogenesis of Epinephelus coioides.