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Blocker oligos

AUMblock sdASO

Self-delivering antisense oligonucleotides for steric blocking of RNA function

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A self-delivering antisense oligonucleotide, one uniform strand with no gap, is taken up by endocytosis and blocks a messenger RNA: single strands drift in the medium outside the cell membrane with no transfection reagent, the membrane takes one in through a pit and a vesicle, one passes through a pore into the nucleus, and in the cytoplasm one is paired at the very start of a messenger RNA, next to its capped end, under a cool faint glow. The two parts of a ribosome sit apart there, the larger above the paired start and the smaller below it, unjoined; no enzyme sits on the pair, nothing is cut, and the messenger RNA runs on whole to its beaded tail past a mitochondrion.

AUMblock sdASOs are steric-blocking antisense oligonucleotides (ASOs) designed to bind target RNAs and modulate their function without recruiting RNase H. Unlike traditional knockdown antisense oligonucleotides, AUMblock sdASOs act as physical blockers on the RNA. They interfere with processes like translation or splicing through steric hindrance, but do not trigger RNase H degradation of the target mRNA.

Many primary cells and disease-relevant models are difficult to transfect with conventional methods. Transfection reagents, electroporation, or viral vectors can introduce toxicity, alter the cellular response, or require additional optimization. Like other AUM products, AUMblock sdASOs are engineered for self-delivery into cells without a transfection reagent, electroporation, or a viral vector. No special conjugates or delivery vehicles are needed. Add them to the culture medium or inject them into an animal. Built on the AUMsilence platform, these blocker oligos achieve high-affinity binding to RNA while avoiding the RNA interference pathway and the RNA-induced silencing complex. They recruit no nuclease to the target RNA, allowing reversible regulation of its function.

  • Steric blocking mechanism

    AUMblock sdASOs bind to their target RNA sequence and physically obstruct the normal binding of cellular machinery, thereby altering RNA function.

  • Reversible RNA modulation

    Because AUMblock sdASO recruits no RNase H to the RNA, the effect is typically reversible – if the ASO dissociates or is metabolized, the RNA can resume normal function.

  • Self-delivery capability

    AUMblock sdASOs possess the same self-delivering properties as our other sdASO products.

  • Sequence design and specificity

    Every AUMblock sdASO is designed by AUM against the target the customer names.

Yields and purification

Available by quote: tell us your target and we design and price it.

Prices and lead time are shown on the order page. Custom yields by quote.

At a glance

Class
Self-delivering antisense (sdASO)
Targets
Steric blocking
Delivery
Add to culture medium or inject in vivo.
Fluorescent label
None

In the lab

The protocol in four steps

The steps below are the AUMblock sdASO protocol's, in its own words. The full protocol carries the amounts per plate format, the tips and the troubleshooting.

Read the full protocol

  1. Step 1

    Cell preparation

    Plate cells in their optimum growth medium at a density appropriate for the cell type. A confluency of 50-70% at the time of treatment is typical.

  2. Step 2

    AUMblock sdASO stock preparation

    Prepare AUMblock sdASO stock solution by reconstituting lyophilized ASOs at the desired concentration. If you already have a stock solution prepared, skip to Step 3.

  3. Step 3

    AUMblock sdASO delivery to cells

    Add AUMblock sdASO to the cells at the desired final concentration. The recommended working range is 5-20 μM, with a starting concentration of 10 μM. The optimal concentration varies with the target gene, the RNA class (messenger RNA, microRNA or long non-coding RNA) and the cell type, and should be determined by titration for each system.

  4. Step 4

    Incubation and analysis

    Incubate cells with AUMblock sdASO and analyze the effect on RNA function at appropriate time points.

FigureThe workflow in cell culture, in four steps

In vitro, the four steps

  1. Step 1

    Prepare cells

    Seed the cells in a 24-well plate; the oligonucleotide waits in solution.

  2. Step 2

    Add to the medium

    Add the self-delivering oligonucleotide straight to the medium: no transfection reagent, no carrier.

  3. Step 3

    Incubate

    Incubate at 37 degrees C in 5% carbon dioxide, humidified, for the exposure time.

  4. Step 4

    Quantify knockdown

    Measure the knockdown: RT-qPCR, immunoblot, flow cytometry.

    Schematic of the three readouts, not data.

For research use only. Not for use in diagnostic or therapeutic procedures.
Sources
  1. The pictures are the object pictures of AUM BioTech's workflow slide, rendered views of the objects on a white ground; none is a photograph of an experiment and none records a measurement.
  2. Tile 04 is a schematic of the three readouts, not data: the two conditions are drawn with a modest difference to show what each readout is, and no magnitude is asserted.

Why

Features of AUMblock sdASO

  • Steric blocking mechanism

    AUMblock sdASOs bind to their target RNA sequence and physically obstruct the normal binding of cellular machinery, thereby altering RNA function. By design, they do not cleave the RNA target – instead, they exert their effects by getting in the way (steric hindrance). This allows for modulation of RNA function without RNase H mediated cleavage.

  • Reversible RNA modulation

    Because AUMblock sdASO recruits no RNase H to the RNA, the effect is typically reversible – if the ASO dissociates or is metabolized, the RNA can resume normal function. This mechanism provides a tunable way to turn down or redirect gene expression at the RNA level.

  • Self-delivery capability

    AUMblock sdASOs possess the same self-delivering properties as our other sdASO products. They enter cells without transfection reagents due to chemical modifications that enable self-delivery, so cells are treated in one step.

  • Sequence design and specificity

    Every AUMblock sdASO is designed by AUM against the target the customer names. Each sequence is scored for specificity against the transcriptome before synthesis. Off-target effects are sequence-dependent and are checked with a non-targeting control.

Mechanism

Mechanism of action

Translation blocking: If an AUMblock sdASO binds in the 5′ untranslated region or across the start codon of an mRNA, it can prevent the ribosome or initiation factors from assembling on that mRNA. This steric blockade of the translation machinery effectively stalls or prevents protein translation from that mRNA without cleaving it.

Splice modulation: If an AUMblock sdASO targets a pre-mRNA at a splice junction, intronic splicing enhancer, or other splicing factor binding site, it can block the recognition of that site by the splicing machinery. This steric hindrance can alter splicing outcomes – for example, causing skipping of an exon or inclusion of an alternative exon – thereby changing the mRNA isoform produced.

MicroRNA (miRNA) and long non-coding RNA (lncRNA) interference: AUMblock sdASOs can also bind to regulatory RNA binding sites. For instance, an AUMblock sdASO complementary to a miRNA's seed-binding site on an mRNA acts as a target protector, preventing that miRNA from binding and repressing the mRNA. Similarly, binding to functional motifs on an lncRNA can block an RNA-binding protein from interacting, thereby modulating the lncRNA's activity.

FigureHow AUMblock sdASO acts
Three stages inside a cell, left to right: one uniform oligonucleotide strand with no gap pairs at the start of a messenger RNA after its capped end, the message running on to its beaded tail; on a second message the two subunits of a ribosome, a larger rounded body above and a smaller one below, approach the paired start under a faint cool halo and cannot close on it; on a third message the subunits have drifted apart to opposite corners while the start stays paired. Every message stays whole, no enzyme appears and nothing is cut. The cell membrane stands at the left, the nucleus at the top right and a mitochondrion at the lower right.
  1. Stage 1

    Like other AUM products, AUMblock sdASOs are engineered for self-delivery into cells without a transfection reagent, electroporation, or a viral vector. No special conjugates or delivery vehicles are needed.

  2. Stage 2

    If an AUMblock sdASO binds in the 5′ untranslated region or across the start codon of an mRNA, it can prevent the ribosome or initiation factors from assembling on that mRNA.

  3. Stage 3

    This steric blockade of the translation machinery effectively stalls or prevents protein translation from that mRNA without cleaving it.

Applications

Applications and use cases

  • mRNA translation inhibition

    By blocking ribosome access, AUMblock sdASO can suppress the production of a specific protein. This is useful for studying protein function (temporary loss-of-function experiments) or knockdown of a protein without RNase H mediated cleavage of the mRNA.

  • Splicing modulation

    AUMblock sdASOs can be directed to alter pre-mRNA splicing patterns. This has applications in correcting aberrant splicing or intentionally skipping an exon. For splice modulation and exon skipping, consider our AUMsplice sdASO product.

  • miRNA blocking

    AUMblock sdASO can function as a miRNA target protector. By binding to the miRNA's target sequence on a given mRNA, it protects that mRNA from miRNA-mediated repression. This approach is useful to validate miRNA–target interactions and to modulate gene expression post-transcriptionally.

  • RNA-protein interaction blocking

    Many RNAs have binding sites for proteins. An AUMblock sdASO can occupy such a motif and act as a decoy, preventing the protein from binding. Assess the functional importance of that interaction by blocking the motif in cells.

Every compatible cell type, 3D model, organoid and in vivo route, with the in vitro workflow.

See where it works

Experimental considerations

The working concentration is higher than that of a transfected oligonucleotide. The recommended working range for AUMblock sdASOs is 5-20 μM. For steric blocking applications, higher concentrations may be required compared to RNA degradation approaches.

Unlike RNA degradation, steric blocking effects should be assessed by functional readouts rather than RNA levels. The readout is the protein, the splice isoform or the interaction the block is aimed at.

In the literature

AUMblock sdASO in published studies

  • Shah et al. · Cell Reports · 2025

    LncRNA SLNCR phenocopies the E2F1 DNA binding site to promote melanoma progression

    An AUMblock sdASO that occupies E2F1 halved melanoma invasion and proliferation, and cells treated before injection then extravasated less into the lungs of mice, without changing the level of either SLNCR or E2F1.

    The study on this site Read the paper

  • Schmidt et al. · Cell Reports · 2020

    Targeting the Oncogenic Long Non-coding RNA SLNCR1 by Blocking Its Sequence-Specific Binding to the Androgen Receptor

    AUMblock sdASOs against the androgen receptor binding motif in the long non-coding RNA SLNCR1, delivered to melanoma cells with no transfection reagent, blocked the interaction and returned invasion to control level while leaving the transcript intact.

    The study on this site Read the paper

  • Schmidt et al. · Cell Reports · 2019

    The lncRNA SLNCR Recruits the Androgen Receptor to EGR1-Bound Genes in Melanoma and Inhibits Expression of Tumor Suppressor p21

    AUMblock sdASOs added to the medium of patient derived melanoma cultures, with no transfection reagent, cut proliferation by breaking the SLNCR to androgen receptor interaction while leaving the long non-coding RNA itself intact.

    The study on this site Read the paper
All publications using AUM BioTech products

At the bench

Protocol, controls and what arrives

Add to culture medium or inject in vivo. The protocol, the controls and the How much to order page are written for this product.

View the protocolControls and validationHow much to orderHow to cite
Lead time
10-14 business days
Shipping
Products are shipped lyophilized, with priority shipping within the United States and international priority shipping elsewhere.
Quality control
Every oligo is strictly controlled for quality and is manufactured in an ISO 9001:2015 certified facility.

Related

Request a quote for AUMblock sdASO

Provide us with your target and the species, and AUM designs the sequences, as part of the price. A scientist is available before ordering to discuss the target and the cell type.

Request a quoteHow to citeView protocols

For research use only. Not for use in diagnostic or therapeutic procedures.