Details

Autor(en) / Beteiligte

• Cyran, Shawn A.
• Buchsbaum, Anna M.
• Reddy, Karen L.
• Lin, Meng-Chi
• Glossop, Nicholas R.J.
• Hardin, Paul E.
• Young, Michael W.
• Storti, Robert V.
• Blau, Justin

Titel

vrille, Pdp1, and dClock Form a Second Feedback Loop in the Drosophila Circadian Clock

Ist Teil von

• Cell, 2003-02, Vol.112 (3), p.329-341

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2003

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The Drosophila circadian clock consists of two interlocked transcriptional feedback loops. In one loop, dCLOCK/CYCLE activates period expression, and PERIOD protein then inhibits dCLOCK/CYCLE activity. dClock is also rhythmically transcribed, but its regulators are unknown. vrille (vri) and Par Domain Protein 1 ( Pdp1) encode related transcription factors whose expression is directly activated by dCLOCK/CYCLE. We show here that VRI and PDP1 proteins feed back and directly regulate dClock expression. Repression of dClock by VRI is separated from activation by PDP1 since VRI levels peak 3-6 hours before PDP1. Rhythmic vri transcription is required for molecular rhythms, and here we show that the clock stops in a Pdp1 null mutant , identifying Pdp1 as an essential clock gene. Thus, VRI and PDP1, together with dClock itself, comprise a second feedback loop in the Drosophila clock that gives rhythmic expression of dClock, and probably of other genes, to generate accurate circadian rhythms.