Alonso J M, Granell A
Departamento de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain.
Plant Physiol. 1995 Oct;109(2):541-7. doi: 10.1104/pp.109.2.541.
A putative citrus vacuolar processing thiolprotease cDNA (Cit-vac) was isolated from a cDNA library of Citrus fruits (Citrus sinensis L. Osbeck var Washington navel). The cDNA is 58 and 57% identical with vacuolar processing seed proteases from castor bean and soybean, respectively. The Citvac sequence shows a typical signal peptide for entering into the endoplasmic reticulum and two glycosylation signals. Using an in vitro transcription-translation system, we show that the Citvac precursor is able to enter a microsomal fraction and to undergo proteolytic processing and glycosylation. Transcript levels for the Citvac are developmentally regulated in the flavedo (outer colored part of the fruit peel) and increase during fruit ripening and in the flower during opening. Exogenous treatment with ethylene induces Citvac mRNA expression in both fruits and leaves. Citvac is encoded by one or two genes in the Citrus genome. The possible role of the Citvac gene product during fruit ripening and other ethylene-mediated processes is discussed.
从柑橘属水果（甜橙，华盛顿脐橙品种）的cDNA文库中分离出一个假定的柑橘液泡加工硫醇蛋白酶cDNA（Cit-vac）。该cDNA与蓖麻和大豆的液泡加工种子蛋白酶分别具有58%和57%的同源性。Citvac序列显示出一个典型的进入内质网的信号肽和两个糖基化信号。利用体外转录-翻译系统，我们发现Citvac前体能够进入微粒体部分并经历蛋白水解加工和糖基化。Citvac的转录水平在果皮外层有色部分（外果皮）受到发育调控，在果实成熟过程中以及花朵开放时增加。用乙烯进行外源处理可诱导果实和叶片中Citvac mRNA的表达。Citvac由柑橘基因组中的一个或两个基因编码。本文讨论了Citvac基因产物在果实成熟及其他乙烯介导过程中的可能作用。
