STABILIZATION OF NEUROFILAMENT TRANSCRIPTS DURING POSTNATAL-DEVELOPMENT

Neurofilament (NF) mRNAs in primary sensory neurons are long-lived tra nscripts th at undergo transcription-dependent destabilization when pl aced in primary culture [32]. Destabilization of NF transcripts implie s that the transcripts are stabilized in high-expressing neurons and t hat stabilization may coordinate and increase levels of NF expression. The present study examines the stabilities of the three NF subunit mR NAs in postnatal cultures of dorsal root ganglia (DRG) to determine wh ether increased stability of NF mRNAs could be responsible for the coo rdinate postnatal upregulation of the three NF subunits [29]. The stud ies show that the light (NF-L), mid-sized (NF-M) and heavy (NF-H) NF m RNAs are lost at 8 and 16 h in primary cultures from postnatal day 2 ( P2) rats, but much less so in cultures from postnatal day 16 (P16) and day 30 (P30) rats. Losses of each NF mRNAs in P2 cultures occurs simu ltaneously in the presence or absence of actinomycin. The findings sup port the view that stabilization of NF transcripts contribute to the h igh and coordinate level NF expression and that components of the stab ilizing process are acquired during postnatal development.