MPK14-mediated auxin signaling controls lateral root development via ERF13-regulated very-long-chain fatty acid biosynthesis

Auxin plays a critical role in lateral root(LR)formation.The signaling module composed of auxin-response factors(ARFs)and lateral organ boundaries domain transcription factors mediates auxin signaling to control almost every stage of LR development.Here,we show that auxin-induced degradation of the APETALA2/Ethylene Responsive Factor(AP2/ERF)transcription factor ERF13,dependent on MITOGENACTIVATED PROTEIN KINASE MPK14-mediated phosphorylation,plays an essential role in LR development.Overexpression of ERF13 results in restricted passage of the LR primordia through the endodermal layer,greatly reducing LR emergence,whereas the erf13 mutants showed an increase in emerged LR.ERF13 inhibits the expression of 3-ketoacyl-CoA synthase16(KCS16),which encodes a fatty acid elongase involved in very-long-chain fatty acid(VLCFA)biosynthesis.Overexpression of KCS16 or exogenous VLCFA treatment rescues the LR emergence defects in ERF13 overexpression lines,indicating a role downstream of the auxin-MPK14-ERF13 signaling module.Collectively,our study uncovers a novel molecular mechanism by which MPK14-mediated auxin signaling modulates LR development via ERF13-regulated VLCFA biosynthesis.

植物超长链脂肪酸及角质层蜡质生物合成相关酶基因研究现状

超长链脂肪酸(very long chain fatty acids,VLCFAs)在生物体中具有广泛的生理功能,它们参与种子甘油酯、生物膜膜脂及鞘脂的合成,并为角质层蜡质的生物合成提供前体物质。角质层是覆盖在植物地上部分最表层的保护层,由角质和蜡质组成,其中蜡质又分为角质层表皮蜡和内部蜡,在植物生长发育、适应外界环境方面起重要作用。VLCFAs的合成由脂肪酰-CoA延长酶催化,该酶是由β-酮脂酰-CoA合酶、β-酮脂酰-CoA还原酶、β-羟脂酰-CoA脱水酶和反式烯脂酰-CoA还原酶组成的多酶体系。合成后的VLCFAs通过脱羰基与酰基还原作用进入角质层蜡质合成途径,形成各种蜡质组分。文章就VLCFAs及角质层蜡质合成代谢途径中相关酶基因研究进展方面做了综述,并对植物蜡质基因研究中存在的问题提出一些看法。

肾上腺脑白质营养不良临床分析(附6例报道)

目的分析肾上腺脑白质营养不良（adrenoleukodystrophy，ALD）的临床和影像学特征。方法对6例ALD患者的临床资料进行回顾性分析。结果6例患者均为男性儿童，年龄为5—12岁，初始症状表现为注意力不集中、情绪不稳定、多动、学习成绩差等，逐渐进展加重，出现肢体瘫痪、共济失调、言语障碍、视听力下降、癫痫发作、意识障碍等。MRI均可见双侧脑室后角周围、顶、枕叶白质区呈对称性蝶翼状长T1及T2信号；可累及胼胝体压部、脑桥及双侧小脑中脚。3例血浆极长链脂肪酸水平升高。脑脊液和脑电图改变无特异性。目前尚无特效治疗方法。结论ALD以儿童脑型常见，依据临床症状和典型的MRI表现可以进行临床诊断。

植物芥酸的研究

芥酸等是重要的VLCFA ,主要存在于少数植物的种子油中。植物中芥酸等VLCFA生物合成是由脂肪酸延长酶催化的 ,在一些植物中 ,该酶系统的有关基因已被克隆研究。人们还从草地泡沫等植物中获得特异性催化芥酸进入Sn - 2位的酶的目的基因。

超长链脂肪酸的研究进展

对超长链脂肪酸的合成代谢途径、生物学功能、分离纯化方法、分析检测技术以及应用等进行综述,并对其研究及应用前景进行了展望。

超长链脂肪酸延伸酶家族的功能及表达调控

超长链脂肪酸延伸酶(elongase of verylong chain fatty acids,ELOVL)家族是哺乳动物中一类编码超长链脂肪酸(very long chain fatty acids,VLCFA)延伸酶的基因家族。该家族有7个成员:ELOVL1～7。各个成员编码的蛋白质参与不同长度脂肪酸链的延长,对脂肪酸的代谢进行调控,进而发挥其生物学功能。本文就该家族成员的结构、生物学功能及表达调控进行综述。

A novel ABCD1 G1202A mutation in a Chinese patient with pure adrenomyeloneuropathy and literature review

Adrenomyeloneuropathy(AMN)is a kind of varied disease caused by ABCD1 gene mutation and characterized by very-long-chain fatty acids(VLCFA)accumulation.It is diag-nosed by clinical features,high VLCFAs levels and ABCD1 gene mutation.AMN is rarely reported in Chinese population.In this study,we report the genetic and clinical features of a Chinese pure AMN patient.Meanwhile,we conducted a literature review of AMN cases to summarize the characteristics of AMN.We report a rare Chinese pure AMN case with slowly progressive weakness of the lower extremities,caused by a novel c.1202G>A mutation in ABCD1 gene.The literature review indicates that spastic paraplegia is the mainly clinical manifestation in patients with AMN.VLCFAs and ABCD1 gene test should be performed in patients with spastic paraplegia of the lower limbs to diagnose AMN.