Technical Data
Internexin, alpha (alpha-Internexin, alpha-Inx, INA, Inexa, 66kD Neurofilament Protein, Neurofilament-66, NF66, NF-66, Neurofilament 5, NEF5)
a-Internexin is a Class IV intermediate filament originally discovered as it copurifies with other neurofilament subunits (1). On SDS-PAGE gels it runs with an apparent molecular weight of 64 to 66kD, with some species variability, although the real molecular weight is about 55kD; as with the other neurofilament subunits the presence of highly negatively charged sequences results in reduction of SDS-PAGE mobility. a-internexin 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 only in neurons and in large amounts early in neuronal development, but is down-regulated in many neurons as development procedes. Many classes of mature neurons contain a-internexin in addition to NF-L, NF-M and NF-H. In some mature neurons a-internexin is the only neurofilament subunit expressed. Antibodies to a-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 a-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 a-internexin during neuronal regeneration (2). 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. Recently Trojanowski, Lee and coworkers used this antibody to show that a-internexin is an abundant component of the inclusions of neurofilament inclusion body disease (NFID, see two Cairns et al. papers listed below), a serious human neurodegenerative disorder. The antibody was also used to confirm the presence of circulating auto-antibodies to a-internexin in the sera of some patients with endocrine autoimmunity, as well as in some normal individuals (Rajasalu et al., 2004, listed below). The HGNC name for this protein is INA.

Suitable for use in Immunofluorescence, Immunohistochemistry and Western Blot. Other applications not tested.

Recommended Dilution:
Immunofluorescence: 1:500
Immunohistochemistry (ABC): 1:5000
Western Blot: 1:10,000
Optimal dilutions to be determined by the researcher.

Storage and Stability:
May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
500ul-20CBlue IceRatMouse
Not determined
Recombinant rat a-Internexin expressed in and purified from E. coli.
Supplied as a liquid.
Recognizes human a-Internexin and with this protein in all mammalian species tested to date.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
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 et al. Axonally transported peripheral signals regulate alpha-internexin expression in regenerating motoneurons. J Neurosci 22:4955-63 (2002).

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