Circadian expression patterns of vrille in peripheral tissues of mutants in Drosophila melanogaster.

The circadian clock of Drosophila (fruit fly) has been extensively studied as a model system in molecular chronobiology. In Drosophila melanogaster, several clock genes are necessary for the generation and regulation of overt rhythms. Among these, vrille (vri) is a clock gene as well as a clock-controlled gene and its oscillation is essential for circadian rhythms at both molecular and behavioral levels. In this study, we have investigated the rhythmic expression patterns of vri at six time points (ZT 02, ZT 06, ZT 10, ZT 14, ZT 18 and ZT 22) over the 24 h period in peripheral tissues such as intestine and salivary glands of wild type (WT) and mutants [vestigial (vg) and cryptochrome absent (cryb)] of D. melanogaster under LD (12:12) condition. At ZT 14, vri expression was most pronounced in WT and mutants in both tissues compared to other time points. At ZT 22 and ZT 02, the expression was almost nil in both tissues. A definite temporal pattern in the levels of vri expression was observed at ZT 06, ZT 10 and ZT 18 in both tissues (of WT and other mutants). vg flies have greatly reduced wings, their gross locomotor activity was poorer and levels of its expression were also lower than WT flies. In cryb mutant, vri expression was less intensive than WT and vg mutants; this indicates that photic transduction to central/peripheral clock(s) is defective in cryb flies compared to other two types. In this study, we observed the presence of circadian expression patterns of vri in the peripheral oscillators during the developmental stages of Drosophila melanogaster. [ABSTRACT FROM AUTHOR]