The circadian role of 2mit, an intronic gene of D. melanogaster timeless2 locus.

Drosophila melanogaster 2mit is a host gene of timeless2 (tim2) locus. 2mit is embedded in intron 11 and transcribed in the opposite direction compared to tim2. Its conceptual translation reveals a putative ransmembrane protein characterized by a leucine-rich repeat (LRR) motif, a conserved domain involved in proteinprotein interactions. 2mit is expressed from the earliest stages of development: in situ hybridization performed in embryos showed that it is prevalently transcribed in the developing Central Nervous System (CNS) and in the medium gut. In adult heads, 2mit mRNA levels show a signifi cant circadian oscillation under 12:12 LD regimes, with higher levels of expression at the end of the night. In adult brains 2mit mRNA localizes at the level of central complex and mushroom bodies, structures involved in the control of locomotor activity and memory. No expression has been detected in the canonical circadian clock neurons. Preliminary results indicate that 2mit mutant adult fl ies, characterized by a ~50% 2mit mRNA decrement, exhibit a free running period of about 26 h in DD. Moreover, similar results were obtained in fl ies with a specifi c 2mit knock-down (KD) driven in the whole nervous system, suggesting a possible function for 2mit in circadian behaviour. In order to explore the putative role of 2mit in the Drosophila circadian clock, we are searching for 2MIT possible interactors screening a Drosophila cDNA library with the yeast two hybrid system. In addition, the PER protein accumulation kinetics in 2mit mutant adult brains is currently under investigation.