英语翻译The function of RNAi in the regulation of SPL3Transcript

英语翻译
The function of RNAi in the regulation of SPL3
Transcripts that contain a miRNA target site are frequently
silenced in an RDR6-dependent fashion when they are expressed
as transgenes,and it has been reported that miRNA-directed
cleavage sensitizes transcripts to transitive silencing (Parizotto et
al.,2004).Consistent with this report,we found that all of our
constructs with a functional miR156 target site were significantly
more susceptible to silencing than constructs that lacked this site.
This made it difficult to generate reporter lines and to maintain
these lines over many generations.It did not interfere with our
ability to identify reliable reporter lines,however,because
transgenes undergoing post-transcriptional silencing have a
different expression pattern than SPL3.Whereas the expression of
SPL3 increases with time,transgenes undergoing silencing are
either permanently silenced very early in shoot development,or
display progressively lower levels of expression during shoot
growth (de Carvalho et al.,1992; Glazov et al.,2003; Palauqui et
al.,1996; Vaucheret et al.,2004).Although it is clear that
transgenes expressing transcripts with miRNA-target sites are
often subject to RNAi,whether this is also true for endogenous
transcripts is less certain.miRNA-directed transitive silencing is
well documented in the case of transcripts that produce transacting
siRNAs (Allen et al.,2005; Yoshikawa et al.,2005).
However,most protein-coding transcripts that are cleaved by
miRNAs – including the miR156-regulatedtranscripts SPL9 and
SPL15 – are not affected by sgs3 or rdr6,and are therefore unlikely
to be targets of RNAi (Allen et al.,2005; Peragine et al.,2004).
The observation that SPL3 and SPL4 are elevated in these mutants
suggests that these genes either have features that make them
unusually susceptible to RNAi (e.g.the presence of the miR156
target site in their 3\2 UTR),or that they are regulated indirectly by
this mechanism – for example,by a transcription factor that itself
is a target of RNAi.We have no conclusive evidence for either
possibility.However,the observation that zip-1,rdr6-11 and sgs3-
11 have nearly identical effects on SPL3 expression (Fig.6A)
(Peragine et al.,2004) suggests that these genes regulate SPL3 by
the same mechanism.Because ZIP is not generally required for
RNAi (Hunter et al.,2003) or for the miR156-dependent
suppression of 35S::GUS-SPL3 (Fig.6C),this observation may
indicate that these genes regulate SPL3 expression indirectly

RNAi在功能调节spl3现场勘验,往往带有目标沉默,在自然资源 一个rdr6依赖性基因表达时, 据报道,自然资源和定点切割敏感性传递给誊沉默(parizotto等. ,2004). 符合本报告 我们发现我们所有的构造与功能mir156靶点显著比沉默更容易 这个网站建构缺乏. 这使记者产生难以维持电缆线许多世代. 它不干预我们辨别可靠线记者,但是 因为基因发生转录后沉默有不同的表达方式,比spl3. 而表达spl3随时间 基因发生沉默不是永久沉默很早拍发展 逐步降低或展示芽生长期间表达层面(DeCarvalho先生等. 1992年; glazov等. ,2003年; palauqui等. 1996年; vaucheret等. ,2004). 显然,尽管基因表达转录与自然资源部靶址屡遭RNA干扰, 无论是真有那么一些源性勘验. 自然资源导向传递沉默是有案可稽的案件,制作笔录交易的siRNA(艾伦等. 2005年; 吉川等. ,2005). 但是 大多数蛋白质编码勘验所切割的植物miRNA包括mir156-regulatedtranscriptsspl9和spl15-不受影响 上传或rdr6,因此不太可能对象RNA干扰(艾伦等. 2005年; peragine等. 、 2004). 长期观察和spl4spl3这些都是高架表明这些基因突变,要么使特色 他们异常容易RNA干扰(如驻留在他们的地盘mir156靶3翻译) 或者是间接的调节机制,例如 这本身就是一种转录因子的目标RNA干扰. 我们没有确凿的证据,无论可能性. 不过,长期观察拉链-1 rdr6-11分解-11几乎相同的效果spl3表达(图1)(peragine等. 、 2004)表明,这些基因相同的规范spl3机制. 拉链不是因为一般需要RNA干扰(猎人等. 、 2003)或为mir156依赖镇压的35S::的GUS-spl3(图6C条) 这表明,这些基因可观测规范间接表达spl3