Volume 17, Number 13,
Issue of July 1, 1997
pp. 4915-4920
Copyright ©1997 Society for Neuroscience
An NF-
B-Like Transcription Factor in Axoplasm is Rapidly
Inactivated after Nerve Injury in Aplysia
Received March 21, 1997; revised April 11, 1997; accepted April 1, 1997.
Michael Povelones1,
Kathy Tran2,
Dimitris Thanos2, and
Richard T. Ambron1
1 Departments of Anatomy and Cell Biology and
2 Biochemistry and Molecular Biophysics, College of
Physicians and Surgeons of Columbia University, New York, New York
10032
We found a protein in Aplysia neurons that has many
characteristics of the transcription factor NF-
B. Thus, the protein
recognized a radiolabeled probe containing the
B sequence from the
human interferon-
gene enhancer element (PRDII), and the binding was not affected by PRDIV, an ATF-2 enhancer sequence from the same gene.
Binding was efficiently inhibited, however, by nonradioactive oligonucleotides containing H2, the
B site from the major
histocompatibility complex I gene promotor. In addition, recombinant
mammalian I
B-
, which associates specifically with the P65 subunit
of NF-
B, inhibited the binding to the PRDII probe in a
dose-dependent manner. The nuclear form of the Aplysia protein
was constitutively active. Axoplasm, however, contained the
constitutively active form as well as a latent form. The latter was
activated by treatment with deoxycholate under the same conditions as
mammalian NF-
B. Based on these findings, we believe the protein to
be a homolog of NF-
B. To investigate the role of apNF-
B in the
axon, we crushed the peripheral nerves to the body wall. Surprisingly,
there was a rapid loss of apNF-
B binding at the crush site and,
within 15 min, as far as 2.5 cm along the axon. In contrast, exposing
either the intact animal or the nervous system in situ
to levels of 5-HT that induce synaptic facilitation did not affect
apNF-
B activity.
Key words:
NF-
B;
axon injury;
transcription factor;
axoplasm;
DNA
binding;
injury signal;
nuclear localization signal