Project description:Short interfering RNAs (siRNA) are widely used as tool for gene inactivation in basic research and therapeutic applications. One of the major shortcomings of siRNA experiments are sequence-specific Off-target effects. Such effects are largely unpredictable because siRNAs can affect partially complementary sequences and function like microRNAs (miRNAs), which inhibit gene expression on mRNA stability or translational levels. Here we demonstrate that novel, enzymatically generated siRNA pools - referred to as siPools - containing up to 60 accurately defined siRNAs eliminate Off-target effects. This is achieved by the low concentration of each individual siRNA diluting sequence-specific Off-target effects below detection limits. In fact, whole transcriptome analyses reveal that single siRNA transfections can severely affect global gene expression. However, when complex siRNA pools are transfected, almost no transcriptome alterations are observed. Taken together, we present enzymatically-produced complex but accurately defined siRNA pools with potent On-target silencing but without detectable Off-target effects. To demonstrate the reduction of Off-target gene deregulation by use of complex siRNA pools (siPools), a single siRNA targeting human SCYL1 was transfected alone or in combination with 14 or 59 other siRNAs at a total siRNA concentration of 3 nM in human Hela cells. Mock transfected cells served as negative control. Every sample was tested in biological triplicates. Total RNA was extract 48h after transfection for affimetrix expression analysis.
Project description:Short interfering RNAs (siRNA) are widely used as tool for gene inactivation in basic research and therapeutic applications. One of the major shortcomings of siRNA experiments are sequence-specific Off-target effects. Such effects are largely unpredictable because siRNAs can affect partially complementary sequences and function like microRNAs (miRNAs), which inhibit gene expression on mRNA stability or translational levels. Here we demonstrate that novel, enzymatically generated siRNA pools - referred to as siPools - containing up to 60 accurately defined siRNAs eliminate Off-target effects. This is achieved by the low concentration of each individual siRNA diluting sequence-specific Off-target effects below detection limits. In fact, whole transcriptome analyses reveal that single siRNA transfections can severely affect global gene expression. However, when complex siRNA pools are transfected, almost no transcriptome alterations are observed. Taken together, we present enzymatically-produced complex but accurately defined siRNA pools with potent On-target silencing but without detectable Off-target effects.
Project description:Short interfering RNAs (siRNA) are widely used as tool for gene inactivation in basic research and therapeutic applications. One of the major shortcomings of siRNA experiments are sequence-specific Off-target effects. Such effects are largely unpredictable because siRNAs can affect partially complementary sequences and function like microRNAs (miRNAs), which inhibit gene expression on mRNA stability or translational levels. Here we demonstrate that novel, enzymatically generated siRNA pools - referred to as siPools - containing up to 60 accurately defined siRNAs eliminate Off-target effects. This is achieved by the low concentration of each individual siRNA diluting sequence-specific Off-target effects below detection limits. In fact, whole transcriptome analyses reveal that single siRNA transfections can severely affect global gene expression. However, when complex siRNA pools are transfected, almost no transcriptome alterations are observed. Taken together, we present enzymatically-produced complex but accurately defined siRNA pools with potent On-target silencing but without detectable Off-target effects.
Project description:Short interfering RNAs (siRNA) are widely used as tool for gene inactivation in basic research and therapeutic applications. One of the major shortcomings of siRNA experiments are sequence-specific Off-target effects. Such effects are largely unpredictable because siRNAs can affect partially complementary sequences and function like microRNAs (miRNAs), which inhibit gene expression on mRNA stability or translational levels. Here we demonstrate that novel, enzymatically generated siRNA pools - referred to as siPools - containing up to 60 accurately defined siRNAs eliminate Off-target effects. This is achieved by the low concentration of each individual siRNA diluting sequence-specific Off-target effects below detection limits. In fact, whole transcriptome analyses reveal that single siRNA transfections can severely affect global gene expression. However, when complex siRNA pools are transfected, almost no transcriptome alterations are observed. Taken together, we present enzymatically-produced complex but accurately defined siRNA pools with potent On-target silencing but without detectable Off-target effects. dsRNA fragments of more than 30bp length may trigger interferon response in mammalian cells, depending on the cell type as well as length and concentration of the dsRNA. To demonstrate that complex siRNA pools (siPools) do not contain trace amounts of such longer dsRNA species and therefore do not trigger interferon response, MCF7 cells which exhibit sensitive interferon response, were transfected with a siPool targeting human SCYL1, consisting of 60 siRNA at a total siRNA concentration of 3nM. As positive control, MCF7 cells were transfected with an RNAseIII generated mixture of dsRNAs (esiRNAs) at equal concentration (weight/volume). Mock transfected cells served as negative control. Every sample was tested in biological triplicates. Total RNA was extract 48h after transfection for affimetrix expression analysis.
Project description:To study the potential target genes regulated by PML in endothelial cells, we carried out siRNA-mediated knockdown of PML in HUVEC cells. To eliminate the off-target effects of siRNAs, we utilized two different siRNAs. Only the genes changed in the same pattern following both siRNAs transfection are considered as potential PML-knockdown responsive genes.
Project description:To study the potential target genes regulated by PML in endothelial cells, we carried out siRNA-mediated knockdown of PML in HUVEC cells. To eliminate the off-target effects of siRNAs, we utilized two different siRNAs. Only the genes changed in the same pattern following both siRNAs transfection are considered as potential PML-knockdown responsive genes. The experiment is one-factor (siRNA) with three ranks (siCtrl, siPML-1, siPML-2). We included technical duplicates for each sample. To minimize systemic errors assoicated with technique, we distributed the duplicates on two different microarray chips.
Project description:WAC is a known positive regulator of (macro)autophagy. WAC also forms a complex with RNF20/RNF40 to promote H2B monoubiquitination and hence to affect transcriptional regulation. This study addresses whether the WAC/RNF20/RNF40 complex regulates autophagy through effects on gene expression. WAC, RNF20 and RNF40 were knocked-down using pools of siRNAs in HEK293A cells. Each knockdown was in triplicate and the control was RISCfree siRNA. mRNA expression profiles were investigated using an Illumina HT12v4 Bead Array.
Project description:To study the interaction effects between promyelocytic leukemia (PML) gene knockdown and tumor necrosis factor-alpha (TNFalpha) signaling in human umbilical vein endothelial cells (HUVECs), we transfected control or two independent PML siRNAs into HUVEC cells without or with 20 ng/mL TNFalpha treatment for 20 h. The total RNA was extracted for gene expression microarray analyses. The experiment is a 3x2 two-factor design. One factor is siRNA and it has three levels (siCtrl, siPML1, siPML2). siCtrl is RISC-inducing non-targeting control siRNA. siPML1 and siPML2 designate two independent siRNAs against the PML gene. Two independent siRNAs were used to eliminate the off-target effects of siRNA. The other factor is TNFalpha treatment (20 ng/mL for 20 h) and it has two levels: Untreated (U) or Treated (T). Each sample has technical duplicates.