SEQUENCE, EXPRESSION AND EVOLUTION OF THE GLOBINS OF THE PARASITIC NEMATODE NIPPOSTRONGYLUS-BRASILIENSIS
SEQUENCE, EXPRESSION AND EVOLUTION OF THE GLOBINS OF THE PARASITIC NEMATODE NIPPOSTRONGYLUS-BRASILIENSIS
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DOI：
10.1016/0166-6851(94)00127-8
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发表时间：
1994-11-01
影响因子：
1.5
通讯作者：
TWEEDIE, S
中科院分区：
文献类型：
--
作者：
BLAXTER, ML;INGRAM, L;TWEEDIE, S
巴西尼波圆线虫的血红蛋白对氧的亲和力比啮齿动物宿主的血红蛋白高100倍。发现了两种同型体，一种位于表皮，另一种位于线虫体内。这两种异构体都已被克隆并分析，以寻找功能和进化的线索。体珠蛋白异构体在入侵哺乳动物宿主时首先表达。丰富的表皮珠蛋白仅在肠道成虫中表达，与体珠蛋白有显著差异。这两种珠蛋白都被发现为反式剪接mRNA: mRNA表达的发育模式与蛋白质表达相似。线虫珠蛋白基因的进化模式是复杂的。与其他线虫珠蛋白序列的比较表明，巴西隐杆线虫与秀丽隐杆线虫的亲缘关系比与蛔虫的亲缘关系更近。至少有两个基因复制事件被预测：基因复制先于重要的脊椎动物寄生线虫物种的辐射。这两种巴西北方人的珠蛋白都有一个中心内含子，其确切位置表明它是由强子-横纹肌系的独立插入事件产生的。这些珠蛋白已经在大肠杆菌中作为功能性全酶表达，作为阐明其非凡氧亲和力起源的研究的前奏。
The globins of the nematode parasite Nippostrongylus brasiliensis have oxygen affinities 100-fold higher than the rodent host's haemoglobins. Two isoforms are found, one located in the cuticle, and the other in the body of the nematode. Both isoforms have been cloned and analysed for clues as to function and evolution. The body globin isoform is first expressed upon invasion of the mammalian host. The abundant cuticular globin is expressed only by adult nematodes in the gut, and differs significantly from the body globin. Both globins are found as trans-spliced mRNAs: the development pattern of expression of the mRNA parallels the protein expression. The pattern of evolution of the nematode globin genes is complex. Comparison with other nematode globin sequences suggest that N. brasiliensis is more closely related to Caenorhabditis elegans than to ascarid species. At least two gene duplication events are predicted: gene duplication preceded the radiation of the important vertebrate-parasitic strongylid nematode species. Both N. brasiliensis globins have a central intron the exact position of which suggests that it arose from an independent insertion event in the strongylid-rhabditid line. The globins have been expressed in Escherichia coli as functional holoenzymes as a prelude to studies to elucidate the origin of their extraordinary oxygen affinity.