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Plexor™ Primers

Custom Plexor™ primers for real-time qPCR, gene expression, SNP genotyping, and multiplex assays using iso-dC / iso-dG fluorescence quenching chemistry.

real-time PCR real-time qPCR gene expression SNP genotyping multiplex assays iso-dC / iso-dG chemistry no separate probe HPLC purified MALDI-MS QC

What Are Plexor™ Primers?

Plexor™ primers are real-time qPCR primers based on the highly specific interaction between two modified nucleotides: isoguanine (iso-dG) and 5′-methylisocytosine (iso-dC). These modified bases form a unique base pair in double-stranded DNA and are designed to pair selectively with each other.

In a Plexor™ assay, the forward primer contains an iso-dC residue and a 5′ fluorescent label. During amplification, DABCYL-labeled iso-dG is incorporated opposite the iso-dC site, bringing fluorophore and quencher into close proximity. As PCR product accumulates, fluorescence is quenched and signal decreases in proportion to product formation.

This makes Plexor™ technology useful for gene expression analysis, SNP genotyping, multiplex qPCR, and assay-development workflows where simple primer design and no separate hydrolysis probe are desired.

No separate probe

Detection chemistry is built into the labeled forward primer and iso-dG system.

Multiplex-ready

Multiple fluorophore channels can support multiplex qPCR assay formats.

Reversible quenching

Melt curve analysis can be performed with Plexor™ chemistry.

Fixed-price options

Listed products are available in standard dye and yield formats.

How Does Plexor™ Primer Chemistry Work?

Plexor™ qPCR signal decreases as amplification product accumulates.

The Plexor™ workflow starts with denaturation of double-stranded DNA, followed by annealing and extension of a 5′ fluorophore-labeled forward primer containing iso-dC. In the next cycle, the reverse primer is extended, and when polymerase encounters iso-dC, a DABCYL-labeled iso-dGTP is incorporated. This brings fluorophore and quencher together and reduces fluorescence.

Plexor primer mechanism showing iso-dC labeled forward primer, DABCYL iso-dG incorporation, and fluorescence quenching during real-time PCR
Plexor™ chemistry uses iso-dC / iso-dG pairing to bring a fluorescent label and DABCYL quencher into proximity as PCR product accumulates.
  • Step 1: target DNA is denatured into single strands.
  • Step 2: the fluorophore-labeled forward primer containing iso-dC anneals and is extended.
  • Step 3: the unlabeled reverse primer extends the complementary strand.
  • Step 4: DABCYL-labeled iso-dG is incorporated opposite iso-dC, reducing fluorescence.
Key concept: unlike probe-based qPCR systems that increase fluorescence, Plexor™ assays measure a reduction in fluorescence caused by iso-dC / DABCYL-iso-dG quenching.

Why Use Plexor™ Primers?

Simple Primer Design

Plexor™ assays use a labeled forward primer and companion reverse primer, reducing the need for separate probe design.

No Separate Probe

Detection is enabled by iso-dC / iso-dG chemistry rather than a separate hydrolysis probe.

Multiplex Capability

Different fluorophore-labeled Plexor™ primers can support multiplex real-time PCR assay formats.

Quantitative qPCR

Signal reduction can be monitored in real time for gene expression and target quantification workflows.

Genotyping Utility

Plexor™ primers are commonly used for SNP genotyping and allele-detection applications.

QC-Backed Supply

Standard Plexor™ primers are HPLC purified and QC tested by MALDI-MS and analytical HPLC.

Plexor™ vs. TaqMan® vs. SYBR® Green

Plexor™ primers occupy a useful middle ground between dye-based qPCR and probe-based qPCR. They avoid a separate hydrolysis probe, while still providing sequence-directed detection through modified-base chemistry.

Feature Plexor™ Primers TaqMan® Probes SYBR® Green
Detection chemistry iso-dC / DABCYL-iso-dG quenching Probe cleavage DNA-binding dye
Separate probe required No Yes No
Multiplex potential High High Limited
Signal direction Fluorescence decreases Fluorescence increases Fluorescence increases
Best use cases Gene expression, SNP genotyping, multiplex qPCR High-specificity quantification and diagnostics Simple singleplex assays and screening
Practical takeaway: Plexor™ is a strong option when you want real-time PCR detection without a separate probe, especially for gene expression, genotyping, and multiplex assay formats.

Plexor™ Primer Services & Pricing

Bio-Synthesis provides fixed-price Plexor™ primer options for gene expression and genotyping, companion reverse primers, and human control gene primer sets. If you need a dye or quencher combination not listed below, contact us.

Plexor™ Primer for Gene Expression and Genotyping

Forward Plexor™ primers include a 5′ fluorescent label and 1 iso-dC modified base. Listed yields are dual HPLC purified.

Forward Plexor™ Primer Item No. OD260 nmole µg Price
5′ FAM + 1 iso-dC modified base PLEP-FAM-02 0.6 2 18.5 $195.00
5′ FAM + 1 iso-dC modified base PLEP-FAM-05 1.5 5 46 $265.00
5′ TAMRA + 1 iso-dC modified base PLEP-TAM-02 0.6 2 18.5 $280.00
5′ TAMRA + 1 iso-dC modified base PLEP-TAM-05 1.6 5 46 $340.00
5′ ROX + 1 iso-dC modified base PLEP-ROX-02 0.5 2 18.5 $280.00
5′ ROX + 1 iso-dC modified base PLEP-ROX-05 1.6 5 46 $340.00
5′ HEX + 1 iso-dC modified base PLEP-HEX-02 0.6 2 18.5 $225.00
5′ HEX + 1 iso-dC modified base PLEP-HEX-05 1.5 5 46 $295.00
5′ Texas Red® + 1 iso-dC modified base PLEP-TEX-02 0.6 2 18.5 $295.00
5′ Texas Red® + 1 iso-dC modified base PLEP-TEX-05 1.5 5 46 $340.00
5′ Cy5® + 1 iso-dC modified base PLEP-CY5-02 0.6 2 18.5 $250.00
5′ Cy5® + 1 iso-dC modified base PLEP-CY5-05 1.5 5 46 $310.00

Plexor™ Unlabeled Companion Primers

Reverse Plexor™ Primer Item No. OD260 nmole µg Price
No label, no iso-dC reverse primer PLEP-REV-10 3 OD 10 95 $20.00

Plexor™ Primers Human Control Gene Primer Sets

Pre-mixed Plexor™ control gene primer sets contain 0.5 nmoles of the Plexor™ primer and an unlabeled companion reverse primer.

Control Gene Primer Set Fluorophore Price
Human GAPDH Primer Set 5′ Texas Red $108.00
Human GAPDH Primer Set 5′ HEX $108.00
Human GAPDH Primer Set 5′ CAL Fluor Orange 560 $108.00
Human GAPDH Primer Set 5′ CAL Fluor Orange Red 610 $108.00
Human GAPDH Primer Set 5′ CAL Fluor Quasar 670 $108.00
β-Actin Primer Set 5′ Texas Red $108.00
β-Actin Primer Set 5′ HEX $108.00
Need a different dye, yield, or assay format?
Bio-Synthesis can help with custom Plexor™ primer design, synthesis, purification, and QC documentation.

Applications of Plexor™ Primers

Gene Expression

Real-time qPCR assays for measuring target expression using labeled forward Plexor™ primers.

SNP Genotyping

Genotyping workflows where modified-base specificity and fluorescent detection support allele analysis.

Multiplex qPCR

Multiple labeled Plexor™ primers can be used across different detection channels for multiplex assays.

Allele Detection

Support for assays where target discrimination and real-time detection are required.

Research Assay Development

Custom primer formats for experimental qPCR assay optimization and screening.

Control Gene Assays

Human GAPDH and β-Actin control primer sets are available in selected fluorophore formats.

Purification, Quality Control, and Specifications

Bio-Synthesis Plexor™ primer products are supplied with purification and analytical QC support appropriate for modified, fluorescently labeled oligonucleotides.

Purification

  • HPLC purified standard options
  • Dual HPLC purification for listed forward Plexor™ primers
  • PAGE or RP-HPLC options for related probe/primer formats

Quality Control

  • MALDI-MS confirmation
  • Analytical HPLC
  • Additional oligo QC options may be available on request

Delivery & Storage

  • Delivered lyophilized
  • Typical listed TAT: 4–7 working days
  • Store dried material at -20 °C to -70 °C
Specification Plexor™ Primer Information
Forward primer length Up to 30 bases for fixed-price Plexor™ forward primers
Backbone Phosphodiester bond
Format Dried-down / lyophilized oligonucleotide product
Shipping Dry, in individual opaque tubes; room-temperature shipping conditions may apply
Technical documentation Oligonucleotide technical data sheet with quantity, sequence-related properties, and purification data where applicable
QC note: modified and fluorescently labeled oligonucleotides should be purified and analytically confirmed to reduce background and support reliable qPCR performance.

FAQ

What are Plexor™ primers?
Plexor™ primers are real-time qPCR primers that use iso-dC / iso-dG modified-base chemistry to generate fluorescence quenching as PCR product accumulates.
How does Plexor™ detection work?
A 5′ fluorescent forward primer contains iso-dC. During amplification, DABCYL-labeled iso-dG is incorporated opposite iso-dC, bringing quencher and fluorophore together and reducing fluorescence.
Do Plexor™ assays require a separate probe?
No. One advantage of Plexor™ chemistry is that it does not require a separate hydrolysis probe.
What applications use Plexor™ primers?
Plexor™ primers are commonly used for gene expression analysis, SNP genotyping, multiplex real-time PCR, allele detection, and assay development.
Can Plexor™ be used for melt curve analysis?
Yes. The quenching effect is reversible, which allows melt curve analysis to be performed with Plexor™ chemistry.
What information is needed for a quote?
Send the target sequence, desired fluorophore, forward primer design if available, companion reverse primer requirement, quantity, purification preference, and application.

Contact & Quote Request

For the fastest review, send your target sequence, desired dye, primer design if available, quantity, purification preference, and intended Plexor™ application.

Fast quote checklist

  • Forward primer sequence or target region
  • Required fluorophore / detection channel
  • Companion reverse primer requirement
  • Gene expression, SNP genotyping, multiplex, or control-gene use
  • Quantity, purification, QC, and delivery requirements

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