Halloween genes are expressed with a circadian rhythm during development in prothoracic glands of the insect RHODNIUS PROLIXUS

Comp Biochem Physiol A Mol Integr Physiol. 2024 Apr;290:111588. doi: 10.1016/j.cbpa.2024.111588. Epub 2024 Jan 18.ABSTRACTWe analyse the developmental and circadian profiles of expression of the genes responsible for ecdysteroidogenesis (Halloween genes) in the PGs of Rhodnius prolixus throughout larval-adult development. Extensive use of in vitro techniques enabled multiple different parameters to be measured in individual PGs. Expression of disembodied and spook closely paralleled the ecdysteroid synthesis of the same PGs, and the ecdysteroid titre in vivo, but with functionally significant exceptions. Various tissues other than PGs expressed one, both or neither genes. Both gonads express both genes in pharate adults (larvae close to ecdysis). Both genes were expressed at low, but significant, levels in UF Rhodnius, raising questions concerning how developmental arrest is maintained in UF animals. IHC confirmed the subcellular localisation of the coded proteins. Gene knockdown suppressed transcription of both genes and ecdysteroid synthesis, with spook apparently regulating the downstream gene disembodied. Transcription of both genes occurred with a daily rhythm (with peaks at night) that was confirmed to be under circadian control using aperiodic conditions. The complex behaviour of the rhythm in LL implied two anatomically distinct oscillators regulate this transcription rhythm. First, the circadian clock in the PGs and second, the circadian rhythm of of Rhodnius PTTH wh...
Source: Comparative Biochemistry and Physiology. Part A, Molecular and integrative physiology. - Category: Physiology Authors: Source Type: research