斑节对虾2种高血糖激素家族基因的基因组序列分析和表达研究

Genome sequence analysis and expression of two CHH genes in tiger shrimp (Penaeus monodon)

  • 摘要: 在斑节对虾(Penaeus monodon)体内新发现了2种高血糖激素(crustacean hyperglycemic hormone, CHH)家族基因PmCHHPmHHLPP。基因组分析结果显示,其均具有CHH-Ⅰ型基因基本的“信号肽-CPRP-KR/ER/RR-成熟肽”结构,且与已报道的CHHs基因的基因组结构相似;聚类分析结果显示,尽管PmCHH PmHHLPP与多个CHHs基因序列相似性超过50% (最高达99%),但与其聚为一支的基因均不是CHH-Ⅰ型基因;生物信息学分析结果显示,PmCHHPmHHLPP的转录起始位点“A”及其核心启动子区域分别位于开放阅读框(ORF)上游的99 bp和190 bp,同时在预测其空间结构后发现,两者的三维结构中均含有4个α螺旋构型;组织表达结果显示,2个基因均在肠中有较高的表达量,而PmCHH在鳃、PmHHLPP在眼柄中表达量也较高,但在肝胰腺和肌肉中表达量较低;幼体发育阶段表达结果显示,2个基因在无节幼体Ⅲ~Ⅳ期、溞状幼体Ⅰ期和糠虾幼体期表达量均有较大波动,与代谢强度呈弱相关关系。根据其一级结构的特征和相关表达情况,可推测PmCHHPmHHLPP均为CHHs家族基因。

     

    Abstract: Two genes encoding crustacean hyperglycemic hormones, named as PmCHH and PmHHLPP, were found in tiger shrimp (Penaeus monodon). In the analysis of genomic sequence, a typical domain of CHH-I gene called CPRP (CHH precursor-related peptide) was found between the signal and the mature peptides in these two genes, and all aligned sequences shared a homogeneous structure of genome. They were alike other CHHs when being blasted in the NCBI. The similarity was over 50% and the maximum was 99%. Besides, PmCHH and PmHHLPP were clustered with the non-CHH-I genes in the phylogenetic analysis. The bioinformatics analysis of their sequences predicts that the transcription initiation site "A" as well as its core promoter region in both genes located at 99 bp and 190 bp upstream of the ORF (open reading frame), and both had four α-helices in the predictive proteins. The expression analysis of different tissues and larval development of P.monodon provides evidence that PmCHH and PmHHLPP could not be easily identified as hyperglycemic genes: the highest expression level was detected in gut, while they expressed low in tissues regulating blood glucose, hepatopancreas and muscle. For the larval development, the stages of Nauplius Ⅲ-Ⅳ, Zoea Ⅰ and Mysis witnessed the peaks and declines of the expression of both genes, which seemed irrelevant to glycemic regulation. In conclusion, PmCHH and PmHHLPP could be identified as members of the CHH family according to their CHH-I like structure.

     

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