Biomedical Research Centre, Sheffield Hallam University, Sheffield S1 1WB, UK.
Plant J. 2012 Apr;70(2):292-302. doi: 10.1111/j.1365-313X.2011.04866.x. Epub 2012 Jan 10.
Auxin is a major growth hormone in plants, and recent studies have elucidated many of the molecular mechanisms underlying its action, including transport, perception and signal transduction. However, major gaps remain in our knowledge of auxin biosynthetic control, partly due to the complexity and probable redundancy of multiple pathways that involve the YUCCA family of flavin-dependent mono-oxygenases. This study reveals the differential localization of YUCCA4 alternative splice variants to the endoplasmic reticulum and the cytosol, which depends on tissue-specific splicing. One isoform is restricted to flowers, and is anchored to the cytosolic face of the endoplasmic reticulum membrane via a hydrophobic C-terminal transmembrane domain. The other isoform is present in all tissues and is distributed throughout the cytosol. These findings are consistent with previous observations of yucca4 phenotypes in flowers, and suggest a role for intracellular compartmentation in auxin biosynthesis.
生长素是植物中的主要生长激素，最近的研究阐明了其作用的许多分子机制，包括运输、感知和信号转导。然而，我们对生长素生物合成控制的认识仍然存在很大的差距，部分原因是涉及黄素依赖的单加氧酶 YUCCA 家族的多种途径的复杂性和可能的冗余性。本研究揭示了 YUCCA4 可变剪接变体在细胞内的差异定位到内质网和细胞质，这取决于组织特异性剪接。一种同工型仅限于花中，并通过疏水性 C 端跨膜结构域锚定在内质网膜的细胞质侧。另一种同工型存在于所有组织中，并分布在整个细胞质中。这些发现与以前在花中观察到的 yucca4 表型一致，并表明细胞内区室化在生长素生物合成中的作用。
