Welin B V, Olson A, Palva E T
Department of Molecular Genetics, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Sweden.
Plant Mol Biol. 1995 Oct;29(2):391-5. doi: 10.1007/BF00043662.
We have isolated a 7 kb EcoRI genomic fragment from Arabidopsis thaliana which contains, in a tandem arrangement, two closely related dhn/lea/rab-like genes, lti29 (formerly named lti45) and cor47, corresponding to previously isolated cDNA clones. Both transcripts have been shown to accumulate in response to low temperature (LT), abscisic acid (ABA) and dehydration. Alignment of the amino acid sequences of the deduced polypeptides showed that they are 67% identical. The calculated molecular masses of the two polypeptides were 29 kDa for LTI29 and 30 kDa for COR47. Both polypeptides contain one conserved serine-stretch and three lysine-rich repeats characteristic of DHN/LEA/RAB-like proteins. In addition, both LTI29 and COR47 harbour and N-terminal acidic repeat only found in a few members amongst the DHN/LEA/RAB proteins. The close distance between the two genes (separated by 2.7 kb) and their tandem organization in the A. thaliana genome as well as the overall homology at the nucleotide sequence level of the coding region suggest that the two genes have evolved through a duplication event. This seems to be a common feature among A. thaliana LT-responsive genes.
我们从拟南芥中分离出一个7 kb的EcoRI基因组片段，该片段以串联排列的方式包含两个密切相关的dhn/lea/rab样基因，即lti29（以前称为lti45）和cor47，它们与先前分离的cDNA克隆相对应。已证明这两种转录本在低温（LT）、脱落酸（ABA）和脱水条件下会积累。推导的多肽氨基酸序列比对显示它们的同源性为67%。两种多肽的计算分子量分别为：LTI29为29 kDa，COR47为30 kDa。两种多肽都含有一个保守的丝氨酸延伸区和三个富含赖氨酸的重复序列，这是DHN/LEA/RAB样蛋白的特征。此外，LTI29和COR47都含有一个仅在少数DHN/LEA/RAB蛋白成员中发现的N端酸性重复序列。这两个基因之间的距离很近（相隔2.7 kb），并且它们在拟南芥基因组中的串联排列以及编码区核苷酸序列水平的总体同源性表明这两个基因是通过复制事件进化而来的。这似乎是拟南芥低温响应基因的一个共同特征。
