摘要： 油体固醇蛋白(steroleosin)是植物的油体中与油体的膜相结合的一种含量较少的固醇结合类短链的脱氢还原酶,根据其分子量可分为固醇蛋白A和B。本文以甘蓝型油菜steroleosin-A和steroleosin-B为关键词下载相关的固醇蛋白基因,并在拟南芥、水稻、甘蓝型油菜、甘蓝和白菜型油菜等18个物种中鉴定其直系同源基因，构建进化树，分析其进化关系。本研究利用GSDS软件对这些基因的基因组DNA序列与编码框CDS序列进行比较，鉴定出内含子和外显子的剪接位点，从而鉴定出这些基因的结构和内含子相位的规律，并以油菜SLO基因的编码序列为探针，以BLAST搜索为手段分别对油菜dbEST数据库进行搜索，同时搜索每一个基因编码序列对应的UniGene，通过分析EST和Unigene数据剖析油菜油体固醇蛋白基因的转录活性。

关键词：甘蓝型油菜；油体固醇蛋白；序列分析

Sequence and Phylogenetic Analysis of the Steroleosin Genes in Brassica napus and Its Parental Species

Abstract: Steroleosin is the short chain dehydrogenase reductase that binds to oil body and oil body membrane in plants. According to their molecular weight, there are two types of steroleosins including steroleosin-A and steroleosin-B. In this paper, Sequences of the steroleosin-a and steroleosin-b in Brassica napus were downloaded and used as queries. Subsequently, orthologous genes from 18 model plants of steroleosin genes were identified by BLAST search. In addition, phylogenetic tree was constructed and phylogenetic relationships of these SLO genes were addressed in detail. In this study, the comparison of genomic DNA and CDS sequences were performed using the the GSDS software, and the splice sites of intron and exon were further identified. Finally, each of the gene structures of these genes was visualized with phrase of intron. The coding sequence of SLO gene was used as the probe, and the BLAST search method was used to search the dbEST and Unigene database. At the same time, all the ESTs were analyzed corresponding to the Unigene, and the presence and absence of EST was determined to predict the transcriptional activity of rapeseed steroleosin genes. The results are of great importance for further study SLO genes in Brasssica species.

Key words: Brassica napus; Steroleosin; Sequence Analysis

目    录

摘要 4

1 引言 5

2 材料与方法 6

2.1 植物材料选取 6

2.2油菜油体固醇蛋白基因的搜索与下载 6

2.3 序列比对与进化关系分析 7

2.4 油菜油体固醇蛋白基因的序列分析 7

2.5 油菜油体固醇蛋白基因的表达分析 7

3 结果与分析 8

3.1 油菜油体固醇蛋白基因的鉴定 8

3.2 油菜及其他植物油体固醇蛋白的系统进化关系 8

3.3 油菜油体固醇蛋白基因的结构特征 10

3.4 油菜油体固醇蛋白的保守基序与功能结构域特点 11

3.5 油菜油体固醇蛋白的跨膜结构域特征 12

3.6 油菜油体固醇蛋白基因的表达规律 13

4 讨论与结论 14

参考文献 15

附录 16

致谢 18

甘蓝型油菜及其亲本物种油体固醇蛋白基因的序列与进化分析

1 引言

通常我们所了解的，有关植物种子中的干营养物质一般主要包括糖类、脂肪和蛋白质等。其中脂肪类则大多数都是以三酰甘油的形式存在存在于种子细胞中，并且TAG在一种称之为油体的间接性亚细胞器中累积，是植物种子中常见的并被公认的主要的脂类营养和化学能储存形式，不过种子中的tag分子之间并不是彼此聚合的，而是分散成了许多小的稳定的亚细胞微滴[1]。油体既然被作为生物体中最小型的细胞器，那么它必定有着其自身的结构和特征，比如说其是由一层致密的单层磷脂膜所包围，内部由不透明的基质构成的；再比如其直径非常小，一般为0.5～2.5µm，更加值得一提的是无论是在活细胞中还是在离体状态下，油体细胞都十分稳定，尤其是在干种子中或在活细胞外经离心分离的上浮液中，油体与油体之间并不会发生融合或聚合，甚至就算是经过了长时间的贮存，它们仍能保持稳定。