Stabilization of neurofilament transcripts during postnatal development.
Neurofilament (NF) mRNAs in primary sensory neurons are long-lived transcripts that undergo transcription-dependent destabilization when placed in primary culture [32]. Destabilization of NF transcripts implies that the transcripts are stabilized in high-expressing neurons and that stabilization may coordinate and increase levels of NF expression. The present study examines the stabilities of the three NF subunit mRNAs in postnatal cultures of dorsal root ganglia (DRG) to determine whether increased stability of NF mRNAs could be responsible for the coordinate postnatal upregulation of the three NF subunits [29]. The studies show that the light (NF-L), mid-sized (NF-M) and heavy (NF-H) NF mRNAs 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 simultaneously in the presence or absence of actinomycin. The findings support the view that stabilization of NF transcripts contribute to the high and coordinate level NF expression and that components of the stabilizing process are acquired during postnatal development.