Characterisation of a bHLH-PAS transcription factor, NPAS1

Abstract

In vitro interaction studies have shown binding between neuronal PAS domain 1 protein (NPAS1) and AhR Nuclear Translocator (ARNT). Using FLAG tagged NPAS1 to pull down other interactors in vivo using HEK293 cells. HSP90, HSP70, tyrosine 3/tryptophan 5-monooxygenase activation protein and ECP-51 are proteins that have been pulled down and then identified using (MALDI/TOF-TOF) and the database search engine, MASCOT v 2.01. The deletion clones of the NPAS1 protein were constructed to try to identify the regions responsible for its repressive activity. The results hint at three regions that have consistently showed repression activity in both systems. Furthermore analysis of the NPAS1 sequence was undertaken with the information provided from the crystal structure of the Drosophila PERIOD (dPER) fragment consisting of two tandemly organized PAS (PER-ARNT-SIM) domains (PAS A and PAS B) and two additional C-terminal helices (E and F).