The Dual Roles of the Golgi Transport 1 (GOT1B): RNA Localization to the Cortical Endoplasmic Reticulum and the Export of Proglutelin and α-Globulin from the Cortical ER to the Golgi
The Dual Roles of the Golgi Transport 1 (GOT1B): RNA Localization to the Cortical Endoplasmic Reticulum and the Export of Proglutelin and α-Globulin from the Cortical ER to the Golgi
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DOI：
10.1093/pcp/pcw154
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发表时间：
2016-11-01
影响因子：
4.9
通讯作者：
Kumamaru, Toshihiro
中科院分区：
文献类型：
--
作者：
Fukuda, Masako;Kawagoe, Yasushi;Kumamaru, Toshihiro
水稻Glup2品系的特征是胚乳57 kDa原谷蛋白和管腔伴侣结合蛋白(Bip)水平异常高，这是内质网(ER)缺陷的特征。为了阐明其潜在的遗传基础，利用基于图谱的克隆方法对GLUP2基因座进行了定位。对3个Glup2等位基因和野生型的DNA测序表明，其潜在的遗传基础是高尔基体转运蛋白1(GOT1B)编码序列的突变。这一结论在GOT1B基因补充的Glup2株系中恢复正常的Proglelin水平进一步得到了验证。显微镜分析表明内质网管腔内存在被醇溶蛋白包涵体包围的脑池内含有谷蛋白原球蛋白的颗粒。通过对发育中的胚乳切片进行原位逆转录聚合酶链式反应(RTPCR)分析，发现醇溶蛋白和α-球蛋白RNA被错误地从蛋白体ER上的正常位置定位到脑池ER，即合成Proglelin的正常位置。我们的结果表明GLUP2/GOT1B在水稻胚乳发育过程中具有双重作用。它是将醇溶蛋白和a-球蛋白RNA定位到蛋白体内质网所必需的，也是将原谷蛋白和a-球蛋白从内质网有效地输出到高尔基体所必需的。
The rice glup2 lines are characterized by their abnormally high levels of endosperm 57 kDa proglutelins and of the luminal chaperone binding protein (BiP), features characteristic of a defect within the endoplasmic reticulum (ER). To elucidate the underlying genetic basis, the glup2 locus was identified by map based cloning. DNA sequencing of the genomes of three glup2 alleles and wild type demonstrated that the underlying genetic basis was mutations in the Golgi transport 1 (GOT1B) coding sequence. This conclusion was further validated by restoration of normal proglutelin levels in a glup2 line complemented by a GOT1B gene. Microscopic analyses indicated the presence of proglutelina- globulin-containing intracisternal granules surrounded by prolamine inclusions within the ER lumen. As assessed by in situ reverse transcriptase polymerase chain reaction (RTPCR) analysis of developing endosperm sections, prolamine and a-globulin RNAs were found to be mis-targeted from their usual sites on the protein body ER to the cisternal ER, the normal sites of proglutelin synthesis. Our results indicate that GLUP2/GOT1B has a dual role during rice endosperm development. It is required for localization of prolamine and a-globulin RNAs to the protein body ER and for efficient export of proglutelin and a-globulin proteins from the ER to the Golgi apparatus.