SUN (Sad1/UNC-84) domain-containing proteins are highly conserved throughout evolution. They are localized to the inner membrane of the nuclear envelope and are involved in nuclear migration and nucleoskeleton formation. In the present study, a genome-wide investigation was performed in three dicotyledonous (Arabidopsis thaliana, Glycine max and Medicago truncatula) and three monocotyledonous (Oryza sativa, Zea mays and Sorghum bicolor) plants. A total of 56 SUN proteins encoded by 30 genes were identified. Based on their length, transmembrane topology, conserved domains and phylogenetic relationships, they could be divided into two previously defined groups- Cter-SUN and mid-SUN proteins. Expression of these genes was analyzed in different developmental stages, tissues and various unfavorable conditions such as salinity, drought, and hormonal treatment. Analyses indicated that the expression of SUN1/2 transcripts are ubiquitous; that of SUN3/4 are development/tissue regulated, and SUN5 are inflorescence stage-specific. This study provides an initial framework for the characterization and functional validation of the plant SUN family.

中文翻译：

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不同植物物种中含有 SUN 结构域的蛋白质的分子进化及其响应发育和扰动刺激的表达谱

SUN (Sad1/UNC-84) 包含结构域的蛋白质在整个进化过程中高度保守。它们位于核膜的内膜，参与核迁移和核骨架形成。在本研究中，对三种双子叶植物（拟南芥、甘氨酸和苜蓿）和三种单子叶植物（水稻、玉米和双色高粱）进行了全基因组调查。共鉴定出由 30 个基因编码的 56 个 SUN 蛋白。根据它们的长度、跨膜拓扑、保守结构域和系统发育关系，它们可以分为两个先前定义的组 - Cter-SUN 和 mid-SUN 蛋白。分析了这些基因在不同发育阶段、组织和各种不利条件（如盐度、干旱、和激素治疗。分析表明SUN1/2转录本的表达无处不在；SUN3/4 是发育/组织调控的，SUN5 是花序阶段特异性的。这项研究为植物 SUN 家族的表征和功能验证提供了一个初步框架。