Catalogue CPCA-a-Int: Chicken Polyclonal Antibody to alpha-Internexin

The Immunogen: Neurofilaments can be defined as the intermediate or 10nm diameter filaments found in neuronal cells. They are composed a mixture of subunits which often includes the neurofilament triplet proteins, NF-L, NF-M and NF-H. Neurofilaments may also include peripherin, alpha-internexin, nestin and in some cases vimentin. a-internexin is a ~66 kDa Class IV intermediate filament originally discovered as it copurifies with other neurofilament subunits (1). It is related to but distinct from the better known neurofilament triplet proteins, NF-L, NF-M and NF-H, having similar protein sequence motifs and a similar intron organization. It is expressed in large amounts early in neuronal development, but is downregulated in many neurons as development procedes. Many classes of mature neurons contain alpha-internexin in addition to NF-L, NF-M and NF-H. In some mature neurons alpha-internexin is the only neurofilament subunit expressed. Antibodies to alpha-internexin are therefore unique probes to study and classify neuronal types and follow their processes in sections and in tissue culture. In addition the very early developmental expression of alpha-internexin means its presence is an early and convenient diagnostic feature of neuronal progenitors cells and other cell committed to the neuronal lineage. In addition recent studies show a marked up-regulation of alpha-internexin during neuronal regeneration (2), and that alpha-internexin positive inclusions are the hallmark of a type of frontotemporal dementia known as neurofilament inclusion body disease (3). The use of antibodies to this protein in the study of brain tumors has not been examined to date, but is likely to be of interest. The HGNC name for this protein is INA.

We are OEM suppliers of this antibody- in other words we manufactured it, characterized it and generated the data presented on this page. This antibody is available from several other vendors, but we can supply it more cheaply and we can provide you with more detailed information on the properties of the antibody.

Left: Western blot of extract of rat brain stem crude extract stained with CPCA-int, showing a single strong clean band at ~66kDa. Right: Mixed neuron glia cultures stain with CPCA-int (red) and counterstained with RPCA-Cor1a, EnCor's rabbit polyclonal antibody to Coronin 1a, (green) which is an excellent marker of microglia and lymphocytes. The chicken internexin antibody is an excellent marker of neuronal processes in these cultures.

Antibody Characteristics:
This antibody was generated in chicken by standard procedures using a full length cDNA encoding rat alpha-internexin as described (4). The resulting polyclonal antibody was extracted from egg yolk and belongs to the IgY subclass. This is the chicken homologue of mammalian IgG and can be used in the same general way, with the caveat that this type of antibody does not bind either Protein A or Protein G. Suitable second antibody reagents can be obtained from many vendors including Molecular Probes and Sigma-Aldrich. Store at 4°C or -20°C. Avoid repeat freezing and thawing.

Suggestions for use: The IgY preparation can be diluted to 1:1,000 and higher for immunofluorescence staining and 1:10,000 and higher for western blotting. On western blots use a brain or spinal cord homogenate and look for a major band at SDS-PAGE apparent molecular weight of 66 to 68kDa. The human protein runs at ~68kDa, while rat, mouse and other species run at ~66kDa. Minor bands at ~150kDa are probably covalent dimers, and bands at ~50kDa represent a-internexin breakdown products.


1. Pachter J and Liem RKH. Alpha-Internexin, a 66-kD intermediate filament-binding protein from mammalian central nervous tissues. J Cell Biol 101:1316-22 (1985)

2. McGraw T. et al. Axonally transported peripheral signals regulate alpha-internexin expression in regenerating motoneurons. J Neurosci 22:4955-63 (2002)

3. Josephs KA et al. Neurofilament inclusion body disease: a new proteinopathy? Brain 126:2291-2303 (2003).

4. Evans J et al. Characterization of mitotic neurons derived from adult rat hypothalamus and brain stem. J. Neurophysiol. 87:1076-85 (2002).

Price and Availability: - We currently supply 100 microliter aliquots for $200. Material is in stock and ready for immediate shipping.

Limitations: This product is for research use only and is not approved for use in humans or in clinical diagnosis.

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