In the September 1 issue of G&D, Dr. Michael Brunner and colleagueshave uncovered the molecular mechanism whereby temperature affectscircadian patterns in the fungus Neurospora. The scientistsinvestigated thermosensitive splicing of the central clockwork protein,FREQUENCY (FRQ), into both long (l) and short (s) isoforms dependingupon temperature.
They found that at low temperatures, intron 6 of frq mRNA ispreferentially spliced, resulting in the exclusion of the l-FRQtranslation initiation site.
This mechanism works alongside atemperature-dependent inhibition of translation by uORFs to effectivelymodulate FRQ levels -- and thereby circadian rhythmicity -- withchanges in ambient temperature.
Dr. Brunner emphasizes that the"interaction of molecular machinery with non-consensus signals - inthis case the interaction of splicing machinery with non-consensussplice sites and the interaction of ribosomes with non-consensustranslation initiation sites - may provide a general mechanism fortemperature-sensing on the molecular level."
Materials provided by Cold Spring Harbor Laboratory. Note: Content may be edited for style and length.
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