Enhanced expression of 14-3-3 family members in injured motoneurons.

Abstract

An increase in 14-3-3 mRNA expression after hypoglossal nerve injury was demonstrated by RNA finger printing using the arbitrary primed polymerase chain reaction (RAP-PCR). RAP-PCR was carried out to compare differences in mRNA expression between axotomized (6 h after the transection) and normal hypoglossal nuclei in mice. The expression of several gene fragments was increased after nerve injury; one fragment was identified as 14-3-3 which is an activator of Raf-1. Since a family of 14-3-3 genes are identified in the rat, we examined the expression of five members of the rat 14-3-3 family after injury (beta, gamma, zeta, eta and theta). Among these family members, a substantial up-regulation in mRNA expression was observed for the zeta and θ forms. Subsequent emulsion autoradiography of hybridization tissue sections revealed an increase in zeta and theta mRNA in injured motoneurons. Since 14-3-3 has the ability to dimerize and activate Raf-1, the up-regulation of 14-3-3 expression would be expected to facilitate the Ras-Erk signal pathway by Raf-1 activation. Our previous results have demonstrated that Shc, Erk1 and Mek1 mRNAs are up-regulated during nerve regeneration, whereas PKA which inhibits the Ras-Erk pathway via Raf-1 was down-regulated. Taken together, the present results suggest that enhancement in expression of molecules involved in the Ras-Erk signaling is required for peripheral nerve regeneration.

• Authors: K Namikawa, Q Su, S Kiryu-Seo, H Kiyama
• Journal: Brain research. Molecular brain research (Brain Res Mol Brain Res) Vol. 55 Issue 2 Pg. 315-20 (Apr 1998) ISSN: 0169-328X [Print] Netherlands
• PMID: 9582444 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 1998 Elsevier Science B.V.

Chemical References

• 14-3-3 Proteins
• Proteins
• RNA, Messenger
• Tyrosine 3-Monooxygenase

Topics

• 14-3-3 Proteins
• Animals
• Axotomy
• Hypoglossal Nerve (physiology)
• In Situ Hybridization
• Male
• Mice
• Mice, Inbred BALB C
• Motor Neurons (metabolism)
• Multigene Family
• Primed In Situ Labeling
• Protein Biosynthesis
• Proteins (genetics)
• RNA, Messenger (biosynthesis)
• Rats
• Rats, Wistar
• Sequence Analysis, DNA
• Tyrosine 3-Monooxygenase