果蝇胚胎不同表达水平基因内含子序列特征的比较分析

Comparative analysis of sequence features of introns with different expression genes of Drosophila embryo

对果蝇胚胎低表达和高表达水平基因内含子的序列结构进行分析,发现2种表达水平的基因内含子序列特征有明显差异.高表达基因的内含子一般比低表达基因的长,其中高表达基因第1内含子的平均长度是低表达基因的2.62倍,第2内含子的平均长度是低表达基因的1.79倍.两类基因第1内含子中的CpG岛含量最高,并且高表达基因内含子中CpG岛含量要高于低表达基因.此外,与低表达基因相比,TATA box、CAAT box和GC box在高表达基因内含子中出现的频数明显要高些,尤其是在第1内含子中.作者还提取出果蝇胚胎2种表达水平基因第1内含子中高频出现的6-mer简单重复序列,发现一些重复序列与实验得到的转录因子结合位点相符合.这些结果提示内含子特别是第1内含子有可能调控果蝇胚胎基因的转录从而影响基因的表达水平.

In this paper,the sequence features of the introns associated with lowly expressed genes and highly expressed genes of Drosophila embryo were studied.The results show that the characteristics of these two kinds of gene introns are significantly different from each other.The average length of the first introns in highly expressed genes is 2.62 times than that in lowly expressed genes.And the average length of the second introns in highly expressed genes is 1.79 times than that in lowly expressed genes.It is found that the CpG islands contents in first introns of two types of genes are higher compared to other introns.Moreover,the CpG islands content in introns of highly expressed genes is higher than lowly expressed genes.In addition,the frequencies of TATA box,CAAT box and GC box occurred in introns of highly expressed genes is significantly higher than those of lowly expressed genes too,especially in first introns.We also extracted 6-mer Simple Sequence Repeat（SSRs） which occurred frequently in the first introns of two different expression genes.Some of these SSRs are accordance with potential transcription factor binding sites（TFBS）,which are verified by experimental analyses.These results provide theoretical evidences for that the introns,especially the first introns,may play an important role in the transcriptional regulation and thus influence the level of expression of Drosophila embryo genes.