Duplication and functional divergence in the chalcone synthase gene family of Asteraceae: Evolution with substrate change and catalytic simplification
Duplication and functional divergence in the chalcone synthase gene family of Asteraceae: Evolution with substrate change and catalytic simplification
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DOI：
10.1073/pnas.93.17.9033
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发表时间：
1996-08-20
影响因子：
11.1
通讯作者：
Albert, VA
中科院分区：
文献类型：
--
作者：
Helariutta, Y;Kotilainen, M;Albert, VA
植物特异性聚酮合酶基因构成了一个基因超家族，包括通用查尔酮合酶[CHS;丙二酰辅酶A：4-香豆酰辅酶A丙二酰转移酶（环化）（EC 2.3.1.74）]基因、零星分布的芪合酶（SS）基因和非典型的、尚未鉴定的CHS样基因。（菊科）一种不寻常的CHS样基因GCHS 2，其编码一种具有结构和酶性质以及不同于CHS和SS的个体发生分布的酶，在此，我们发现GCHS 2-like功能在非洲菊基因组中由至少三个转录活性基因组成的家族编码，利用GCHS 2家族内的保守性，用选择性PCR研究GCHS 2-like基因在其他菊科植物中的存在。对扩增序列以及从被子植物菊科其他类群中分离的CHS样基因的简约性分析表明，GCHS 2是通过在菊科多样化之前发生的基因复制事件从CHS进化而来的。体外产生的蛋白质的酶活性分析表明，GCHS 2反应是CHS反应的非SS变体，与Durbin艾德等人，[Durbin，M. L.，学着点，G。H、小的，Huttley，G. A. & Clegg，M. T.等人（1995）Proc. Acad. Sci. USA 92，3338-3342]，我们的研究证实了一个基于基因复制的模型，该模型解释了在植物进化过程中CHS如何产生各种相关功能。
Plant-specific polyketide synthase genes constitute a gene superfamily, including universal chalcone synthase [CHS; malonyl CoA:4-coumaroyl-CoA malonyltransferase (cyclizing) (EC 2.3.1.74)] genes, sporadically distributed stilbene synthase (SS) genes, and atypical, as-yet-uncharacterized CHS-like genes, We have recently isolated from Gerbera hybrida (Asteraceae) an unusual CHS-like gene, GCHS2, which codes for an enzyme with structural and enzymatic properties as well as ontogenetic distribution distinct from both CHS and SS, Here, we show that the GCHS2-like function is encoded in the Gerbera genome by a family of at least three transcriptionally active genes, Conservation within the GCHS2 family was exploited with selective PCR to study the occurrence of GCHS2-like genes in other Asteraceae. Parsimony analysis of the amplified sequences together with CHS-like genes isolated from other taxa of angiosperm sub-class Asteridae suggests that GCHS2 has evolved from CHS via a gene duplication event that occurred before the diversification of the Asteraceae, Enzyme activity analysis of proteins produced in vitro indicates that the GCHS2 reaction is a non-SS variant of the CHS reaction, with both different substrate specificity (to benzoyl-CoA) and a truncated catalytic profile, Together with the recent results of Durbin ed al, [Durbin, M. L., Learn, G. H., Jr., Huttley, G. A. & Clegg, M. T. (1995) Proc. Natl. Acad. Sci. USA 92, 3338-3342], our study confirms a gene duplication-based model that explains how various related functions have arisen from CHS during plant evolution.