描述：
siRNA产品概述
通过SMARTselectionTM技术所设计的siRNA被证明可广泛沉默人、小鼠和大鼠基因组的任何已知基因。每个基因的siRNA试剂可以SMARTpool®产品或者单条的siRNA提供，方便客户的选择。每个SMARTpool®产品由四条不同的siRNA按照一定的比例混合而成，确保对靶基因有至少75％的沉默效果。这4条siRNA的序列信息会随产品一同发给客户。
Dharmacon的SMARTselectionTM理性设计技术可以确保我们成功的预测有功能的siRNAs，但有可能会忽略siRNA正义链所引起的非特异靶点的沉默。既然已经认识到这一点，Dharmacon通过ON-TARGETTM技术，可以最小化正义链的活性，从而使之不能引起基因的非特异沉默。这种ON-TARGETTM技术是Dharmacon独有的专利技术，可对siRNA的正义链进行化学修饰（详见ON-TARGETTM技术介绍部分）。ON-TARGETTM修饰技术使得Dharmacon可最大化提供给研究者潜在的、功能性siRNA的数量，目前已涵盖了人、小鼠和大鼠全基因组大约81,000个基因的siRNA试剂，从而成为本行业最全面、最灵活选择的基因沉默试剂。
ON-TARGETTM技术应用核酸的生物化学和生物物理学的特性，限制了siRNA正义链和RNA诱导沉默复合物（RNA-induced Silencing complex, RISC）结合，而反义链的功能性和特异性得到维持或者加强，因此，将正义链所引起的脱靶效应降到最低。
为了最大化的提高基因沉默的特异性，同时又不牺牲siRNA产品的效率。许多产品中的一条或多条siRNA均经过ON-TARGETTM技术修饰。所有的siRNA产品均可以在Dharmacon网站的搜索引擎中找到。
siRNA产品特点：
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即开即用，提供任何已收集在NCBI参考序列数据库中的人、小鼠和大鼠基因的siRNA试剂。
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先进的SMARTselectionTM技术确保产品的功能性和特异性。
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SMARTpool®产品可保证靶基因沉默至少75％。
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不管是SMARTpool®产品还是单条的siRNA产品，均提供每条siRNA序列信息。
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全面和灵活的产品形式（siGENOMETM 或者ON-TARGETplus, SMARTpool®或者单条siRNA）可广泛应用于各个领域的研究。
siRNA：高效特异性基因沉默试剂
下图表示的是用SMARTselectionTM技术所设计了10个不同的人、小鼠基因的siRNA和SMARTpool® siRNA试剂的高效沉默表现。SMARTpool® siRNA试剂相当甚至超越了单独的siRNA试剂的基因沉默效果。尽管运用单独的siRNA试剂可以达到高效沉默效果，但是运用SMARTpool® siRNA试剂可以有效避免脱靶效应并增强基因沉默效果。
ON-TARGET修饰增强基因沉默特异性
ON-TARGET修饰方式可以进一步增强许多小鼠和大鼠基因沉默的特异性，在最小化脱靶效应的同时提供了基因沉默实验额外的信赖保证。这种修饰方式抑制了siRNA正义链与RISC的结合，根本上排除了正义链参与的脱靶效应。这种修饰可以确保特异性靶向基因沉默的卓越表现。
对反义链（antisense,AS）进行ON-TARGET修饰显著降低了正义链的功能性（见下图），因此，对正义链同样的修饰方式可以完全排除正义链所引发的脱靶效应。这种假设通过基因芯片检测将siRNA正义链修饰后靶向特定基因的结果中得到证实。下图的“heat map”图谱表示siRNA双链在不做任何修饰、正义链修饰或者反义链修饰等情况下的脱靶效应。
Figure . Silencing potency of siRNAs containing ON-TARGET™ modifications. (A) Three different siRNAs, targeting human
cyclophilin B mRNA, were individually tested in a) unmodified, b) antisense strand modi-fied, and c) sense strand modified
forms for their ability to direct mRNA degradation in HEK293 cells. In all three cases, unmodified duplexes efficiently silenced the target. When ON-TARGET™ Modifications were applied to the antisense strand (S-*AS), duplex functionality was
eliminated, probably because the antisense strand (the strand responsible for directing gene-specific silencing) is unable to associate with the RISC. In contrast, when the same modifications are applied to the sense strand only (*S-AS), the silencing potency of the duplex is maintained or increased (ns = nonspecific; Control = non-targeting siRNA).(B) A heat map resulting from microarray studies illustrates the off-target expression profile of cells treated with unmodified and modified siRNAs directed against Gene A. Note that in this case, modification of the sense strand eliminates the majority of the off-target signature (illustrated primarily in the boxed region). When only the antisense strand is modified, off-target effects occur (blue = down-regulation, black = no effect, pink = up-regulation). (Heat map data presented with permission from A. Jackson and P.S. Linsley, Rosetta Inpharmatics LLC.) B.
siRNA产品信息
Dharmacon的siRNA试剂是最全面的基因沉默平台，提供给本行业最先进、最成功和最广泛使用的siRNA试剂，确保全球的科学家可以在最短的时间内从RNA干扰技术中获得巨大的收益。目前为止已涵盖了包括人、小鼠和大鼠三个物种的基因组范围内的所有已知基因，持有最大的潜在功能的siRNA数据库，超过确保沉默81,000（包括人，小鼠，大鼠）个基因的相关siRNA试剂。
SMARTpool® siRNA试剂
产品特点：
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是由SMARTselectionTM技术所设计的四条siRNA双链的混合物；
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提供混合物中每条siRNA序列信息。
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即开即用型沉默试剂包括人、小鼠和大鼠NCBI基因序列数据库中的所有基因的siRNA；
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降低浓度依赖性的非特异效应和脱靶效应
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独有的SMARTselection技术确保高效、特异性的沉默效果；保证标准条件下沉默基因水平至少75%；超过85％的SMARTpool siRNA试剂的沉默水平可达90%甚至更高。
原厂资料：
Thermo Scientific siGENOME siRNA reagents are widely recognized and trusted for highly efficient target gene silencing. Our scientists were the first to establish siRNA design rules for high potency silencing and continue to drive innovation in this area. By providing genome-wide siRNAs designed with the SMARTselection algorithm, researchers can focus on successful RNAi experiments instead of optimizing siRNA designs for their genes of interest.
siGENOME siRNA is available as pre-designed, genome-wide SMARTpool and individual siRNA reagents for human, mouse and rat. Simply search for your gene of interest and choose from the available product formats and quantities.
Highlights
Guaranteed knockdown by SMARTpool and 3 of 4 individual siRNAs (see Specifications)
Antisense strand loading into RISC ensured by thermodynamic analysis and selective application of a sense strand-blocking modification (ON-TARGET)
Sequence information provided with siRNA purchase
Design and modification strategies for optimal silencing
In addition to identifying potent siRNA designs with the SMARTselection algorithm, the creation of siGENOME siRNAs also involves
Thermodynamic analysis to determine optimal antisense strand-loading characteristics for effective silencing
BLAST analysis of both strands to alleviate cross-targeting
To retain more high-scoring siRNA designs, the above analysis may trigger the use of a sense strand-blocking modification (ON-TARGET) to ensure only the appropriate strand enters RISC for effective target knockdown (see Figure 2, Supporting Data).
Available Product Formats
SMARTpool: A mixture of 4 siRNA provided as a single reagent; providing advantages in both potency and specificity. siGENOME and ON-TARGETplus guaranteed to silence by 75% or better (see Specifications).
Set of 4: A convenient option for purchasing aliquots of all 4 individual siRNAs targeting a single gene. Three of four siGENOME and ON-TARGETplus siRNAs are guaranteed to silence by 75% or better (see Specifications).
Set of 4 Upgrade: Discounted price on the Set of 4 based on a concurrent or prior purchase of the SMARTpool reagent for the same gene.
Individual siRNAs: Select 1, 2, 3 or 4 individual siRNAs per gene. Minimum purchase of 4 at the 2 nmol size.
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