miR319a targeting of TCP4 is critical for petal growth and development in Arabidopsis
miR319a targeting of TCP4 is critical for petal growth and development in Arabidopsis
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DOI：
10.1073/pnas.0908718106
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发表时间：
2009-12-29
影响因子：
11.1
通讯作者：
Jack, Thomas
中科院分区：
文献类型：
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作者：
Nag, Anwesha;King, Stacey;Jack, Thomas
在drnl-2背景下的遗传筛选中，我们分离了miR 319 a中的功能丧失等位基因（miR 319 a（129））。以前，基于异位表达miR 319 a（jaw-D）的植物的显著卷曲叶表型，miR 319 a被假定在叶发育中起作用。miR 319 a（129）突变体在花瓣和雄蕊发育中表现出缺陷;花瓣窄而短，并且雄蕊在花药发育中表现出缺陷。miR 319 a（129）功能丧失等位基因在编码的miRNA中间含有单碱基变化，这降低了miR 319 a识别靶标的能力。miR 319基因家族的三个成员（miR 319 a、miR 319 b和miR 319 c）的表达模式的分析表明，这些基因具有很大程度上不重叠的表达模式，表明这些基因具有不同的发育功能。miR 319 a通过调节TCP转录因子TCP 2、TCP 3、TCP 4、TCP 10和TCP 24发挥功能;这些TCP基因的RNA表达水平在jaw-D中下调，而在miR 319 a中升高（129）。几条证据表明，TCP 4是miR 319 a的关键靶标。首先，tcp 4（soj 6）突变体，其在与miR 319 a（129）突变互补的TCP 4 miRNA结合位点中含有突变，抑制miR 319 a（129）的花表型。第二，野生型TCP 4在花瓣和雄蕊中的表达（即，AP 3：TCP 4）对花发育没有影响;相反，当在花瓣和雄蕊中表达时，pAP 3：mTCP 4）导致这些器官不发育。令人惊讶的是，当AP 3：TCP 4存在于miR 319 a（129）背景中时，花瓣和雄蕊发育被严重破坏，这表明通过miR 319 a对TCP 4的适当调节在这些花器官中是至关重要的。
In a genetic screen in a drnl-2 background, we isolated a loss-of-function allele in miR319a (miR319a(129)). Previously, miR319a has been postulated to play a role in leaf development based on the dramatic curled-leaf phenotype of plants that ectopically express miR319a (jaw-D). miR319a(129) mutants exhibit defects in petal and stamen development; petals are narrow and short, and stamens exhibit defects in anther development. The miR319a(129) loss-of-function allele contains a single-base change in the middle of the encoded miRNA, which reduces the ability of miR319a to recognize targets. Analysis of the expression patterns of the three members of the miR319 gene family (miR319a, miR319b, and miR319c) indicates that these genes have largely non-overlapping expression patterns suggesting that these genes have distinct developmental functions. miR319a functions by regulating the TCP transcription factors TCP2, TCP3, TCP4, TCP10, and TCP24; the level of RNA expression of these TCP genes is down-regulated in jaw-D and elevated in miR319a(129). Several lines of evidence demonstrate that TCP4 is a key target of miR319a. First, the tcp4(soj6) mutant, which contains a mutation in the TCP4 miRNA-binding site complementary to the miR319a(129) mutation, suppresses the flower phenotype of miR319a(129). Second, expression of wild-type TCP4 in petals and stamens (i.e., AP3:TCP4) has no effect on flower development; by contrast, a miRNA-resistant version of TCP4, when expressed in petals and stamens (i.e.,pAP3:mTCP4) causes these organs not to develop. Surprisingly, when AP3:TCP4 is present in a miR319a(129) background, petal and stamen development is severely disrupted, suggesting that proper regulation by miR319a of TCP4 is critical in these floral organs.