乌鳢globin基因家族的鉴定及在鳃和鳃上器官中的表达模式分析

Identification of globin Gene Family in Channa argus and Analysis of Its Expression Pattern in Gill and Suprabranchial Organ

为了探究珠蛋白(Globin)在具有耐低氧和空气呼吸能力的乌鳢(Channa argus)中发挥的作用,本文对乌鳢的globin基因家族进行研究。在基因组中鉴定得到18个globin基因,分属于Hb、Mb、Ngb和Cygb四个亚家族,其中Hb亚家族拷贝数最多,达14个,其余各亚家族仅有1~2个拷贝。系统进化分析表明,乌鳢globin基因与硬骨鱼类聚为一枝,在进化上较为保守。对乌鳢globin基因结构分析得到4种保守结构域和5个motif。利用转录组测序技术对仔稚鱼(受精后3~8 d)和幼鱼(4月龄)的鳃和鳃上器官中globin基因进行表达量检测。在仔稚鱼中,hbae1(包括hbae1.1、hbae1.2和hbae1.3)、hbb2(包括hbb2.1、hbb2.2和hbb2.4)和hbaa的表达量在鳃上器官发育过程中呈显著升高趋势,而hba1和hbb1的表达量则显著降低。在幼鱼中,在空气暴露胁迫后,hbb2.2和cygb的表达量在鳃和鳃上器官中均发生显著变化,hbae1.1、hbae1.2和hbba的表达量在鳃中发生显著变化,hbae1.3和hbb2.1的表达量在鳃上器官中发生显著变化。这些在鳃上器官发育过程中和空气暴露胁迫中表达量出现显著变化的globin基因可能在乌鳢空气呼吸及低氧胁迫中发挥了生物学功能。

To investigate the role of Globin in Channa argus which is hypoxia-tolerant and air-breathing,the globin gene family of C.argus was studied.Eighteen globin genes were identified in the genome,which belonged to four subfamilies,Hb,Mb,Ngb and Cygb,among them Hb subfamily had the highest copy number(14),and the rest of the subfamilies had only 1~2 copies.Phylogenetic analysis showed that the globin genes of C.argus were clustered with osteichthyes and were evolutionarily conserved.The gene structure analysis of C.argus globin genes revealed 4 domains and 5 motifs.The expression of globin genes in gill and suprabranchial organ of larvae(3~8 days post fertilization)and juvenile(4 months old)was examined through RNA-seq.In larvae,the expression of hbae1(including hbae1.1,hbae1.2 and hbae1.3),hbb2(including hbb2.1,hbb2.2 and hbb2.4)and hbaa were significantly high during the development of suprabranchial organ while the expression of hba1 and hbb1 was significantly low.In juvenile,following air exposure stress,the expression of hbb2.2 and cygb changed significantly in both gill and suprabranchial organ whereas expression of hbae1.1,hbae1.2 and hbba changed significantly in gill,hbae1.3 and hbb2.1 changed significantly in suprabranchial organ.These globin genes showing significant changes in expression during suprabranchial organ development and air exposure stress may perform biological functions in air-breathing and hypoxia stress in C.argus.