Featuring:
Skip Navigation Links.
 Plus quality reagents for:
Skip Navigation Links.

 
    
All of Vector’s nucleic acid labeling kits are non-radioactive and offer many advantages over radioactivity, including excellent sensitivity in a shorter period of time; prolonged stability of reagents and labeled probes; and choices of detection and affinity binding matrices. Vector’s labeling systems employ different approaches which (1) incorporate the label at multiple sites along the entire length of the nucleic acid, or (2) incorporate the label only at the 3’ or 5’ end.

For those new to the field or those seeking straightforward, cost effective approaches in optimal labeling and detection of DNA/RNA probes please see the following Molecular Biology Guide. Instructive diagrams showing labeling methodologies are accompanied by photographic examples submitted by independent investigators that highlights their recent research. Practical insight is offered into choice of labeling method based on probe size, type, application and tag. Subsequent detection of the labeled probes using chromogenic or fluorescent visualization is described for various applications including microarrays, blotting and in situ hybridization. Step-by-step protocols and referenced publications make this a valuable and contemporary reference tool. You may download a copy here or request a free copy on our Catalog & Brochures request page under the Support menu.
MBB.pdf (PDF)
Choosing a Labeling Method

When labeling nucleic acids, two considerations determine which labeling system will work best for a given application:

  • size and type of the nucleic acid to be labeled
  • choice of label required for the application

    Size and Type

    Longer strands of DNA (>100 bp), circular DNA (i.e. plasmid DNA), RNA, or PNA (peptide nucleic acid) are efficiently and reliably labeled with the PHOTOPROBE® labeling reagents or the FastTag® Nucleic Acid Labeling System. With these chemical labeling methods, Vector Laboratories offers an alternative to traditional enzymatic labeling methods such as random priming or nick translation which are difficult to control and don’t label the original nucleic acid sample. While random priming or nick translation result in a labeled copy produced from the original template, PHOTOPROBE® labeling reagents and the FastTag® systems ensure labeling of the original nucleic acid. Multiple site labeling over the entire length of the nucleic acid with PHOTOPROBE® labeling reagents and FastTag® systems results in greater accessibility of the affinity tag or increased detection sensitivity.

    The integrity of the nucleic acid is preserved in this nondestructive reaction making it useful for applications where it is necessary to use the intact, original sample. The PHOTOPROBE® or FastTag® chemical labeling method is especially convenient for labeling samples that will be used to observe cellular localization of nucleic acid (e.g. plasmid DNA in gene delivery or siRNA) or for quantitative comparison.

    Shorter strands of nucleic acids such as oligonucleotides, PCR primers, or capture probes used to identify nucleic acid binding proteins are specifically and efficiently labeled at either the 5’ or the 3’ end using the 5’ EndTag™ or the 3’ EndTag™ Nucleic Acid Labeling Systems, respectively. The 5’ EndTag™ or the 3’ EndTag™ Kits can be used to attach a single fluorochrome or affinity tag at the appropriate end of nucleic acids. The 5’ EndTag™ Labeling Kit uses both DNA and RNA as a substrate, whereas the 3’ EndTag™ Kit will selectively label only DNA.

    • Choice of Label

    The second important factor in determining the most appropriate labeling system is the choice of label or affinity tag required for the application. The PHOTOPROBE® Biotin reagents incorporate biotin into nucleic acid in one simple step. The versatility of the FastTag®, 5’ EndTag™ or 3’ EndTag™ Labeling Kits, or PHOTOPROBE® Amine allows a variety of tags to be incorporated including fucose for reversible binding.

    Some commonly used labels that are available from Vector Laboratories are:

    Biotin – The extraordinary affinity of avidin and streptavidin for biotin and the many biotin-avidin/streptavidin systems available make this label ideal for a variety of applications including in situ hybridization, blotting, and affinity binding.

    DNP (Dinitrophenyl) – DNP is not found endogenously in tissue so it is an excellent alternative to biotin. High affinity, purified antibodies are available for detection or amplification of the signal.

    Fluorescein – Fluorescein is not found endogenously in biological systems. This fluorescent label can be visualized directly (ex 495 nm; em 515 nm) or used as a hapten and detected with our biotinylated or enzyme-conjugated antibody to fluorescein.

    Texas Red® - Texas Red® is also not found endogenously in tissues. This fluorescent label is a high quantum yield rhodamine that can be directly visualized (ex 595 nm; em 615 nm). The label can also be detected, and the signal amplified, using our biotinylated or alkaline phosphatase conjugated antibody to rhodamine.

    Fucose – This unique label is ideal for reversible binding of labeled nucleic acid to VECTREX® AAL, a matrix containing the fucose-specific lectin Aleuria aurantia. Fucose-labeled nucleic acids can be bound and eluted under mild conditions. Alkaline phosphatase conjugated Aleuria aurantia lectin can be used in dot blot applications to assess labeling efficiency with the fucose label.