Cheng R, Ford B L, O'Neal P E, Mathews C Z, Bradford C S, Thongtan T, Barnes D W, Hendricks J D, Bailey G S
Department of Food Science and Technology, Oregon State University, Corvallis 97331-6602, USA.
Mol Mar Biol Biotechnol. 1997 Jun;6(2):88-97.
Three methods were used in succession to screen a whole adult zebrafish cDNA library for expressed p53-like genes. The sequences of the resultant clones describe an open reading frame 1122 nucleotides in length, with another 43 and 940 bases of 5' and 3' untranslated sequence, respectively. The deduced amino acid sequence of the zebrafish p53 protein is 63% identical to that of trout and 48% identical to that of human p53. Two of the three zebrafish clones overlap to span the entire reported cDNA sequence and are identical in their deduced amino acid sequence over their coincident length. The third clone contains a conservative amino acid change, as well as an inserted amino acid subsequently found to be at the junction of exons 2 and 3, suggestive of alternative splicing in the p53 mRNA for this species. Northern analysis demonstrated a zebrafish p53-related transcript to be present and most abundant in zygotes and early-cleavage embryos less than 1 hour after fertilization, thereafter declining to barely detectable levels at 48 hours. A similar temporal expression was detected for the zebrafish L-myc, known to be present in maternally derived RNA, whereas zebrafish N-myc and the zebrafish homologue of the murine T gene were not detectable prior to the onset of zygotic transcription.
我们连续使用了三种方法来筛选成年斑马鱼的全长cDNA文库，以寻找表达的p53样基因。所得克隆的序列描述了一个长度为1122个核苷酸的开放阅读框，其5'和3'非翻译序列分别还有43个和940个碱基。斑马鱼p53蛋白的推导氨基酸序列与鳟鱼的序列有63%的同源性，与人类p53有48%的同源性。三个斑马鱼克隆中的两个相互重叠，覆盖了整个报道的cDNA序列，并且在它们重叠的长度范围内，推导的氨基酸序列相同。第三个克隆包含一个保守的氨基酸变化，以及一个随后被发现位于外显子2和3交界处的插入氨基酸，这表明该物种的p53 mRNA存在可变剪接。Northern分析表明，斑马鱼p53相关转录本存在，并且在受精后不到1小时的受精卵和早期分裂胚胎中最为丰富，此后在48小时时降至几乎检测不到的水平。对于已知存在于母源RNA中的斑马鱼L-myc，也检测到了类似的时间表达模式，而斑马鱼N-myc和小鼠T基因的斑马鱼同源物在合子转录开始之前无法检测到。
