Format

Send to

Choose Destination
J Neurosci. 2015 Jun 3;35(22):8662-71. doi: 10.1523/JNEUROSCI.0250-15.2015.

Circadian Activators Are Expressed Days before They Initiate Clock Function in Late Pacemaker Neurons from Drosophila.

Author information

1
Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas 77845-3258.
2
Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, Texas 77845-3258 phardin@bio.tamu.edu.

Abstract

Circadian pacemaker neurons in the Drosophila brain control daily rhythms in locomotor activity. These pacemaker neurons can be subdivided into early or late groups depending on whether rhythms in period (per) and timeless (tim) expression are initiated at the first instar (L1) larval stage or during metamorphosis, respectively. Because CLOCK-CYCLE (CLK-CYC) heterodimers initiate circadian oscillator function by activating per and tim transcription, a Clk-GFP transgene was used to mark when late pacemaker neurons begin to develop. We were surprised to see that CLK-GFP was already expressed in four of five clusters of late pacemaker neurons during the third instar (L3) larval stage. CLK-GFP is only detected in postmitotic neurons from L3 larvae, suggesting that these four late pacemaker neuron clusters are formed before the L3 larval stage. A GFP-cyc transgene was used to show that CYC, like CLK, is also expressed exclusively in pacemaker neurons from L3 larval brains, demonstrating that CLK-CYC is not sufficient to activate per and tim in late pacemaker neurons at the L3 larval stage. These results suggest that most late pacemaker neurons develop days before novel factors activate circadian oscillator function during metamorphosis.

KEYWORDS:

cell determination; circadian clock; clock proteins; gene expression; pacemaker neurons

PMID:
26041931
PMCID:
PMC4452561
DOI:
10.1523/JNEUROSCI.0250-15.2015
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center