| Insect reproductive success depends on their ability to read their environment. One of the sensory channels used to that effect is olfaction. Insects use highly specialized structures called sensilla to capture and decode odorants. One of the molecular supporting their physiology includes the odorant-binding proteins (OBPs). OBPs are thought to transport odorants to the odorant receptors in olfactory sensilla. Various olfactory sensilla display a typical structure and molecular phenotype. How and when, as the adult develops, are these sensilla established? This work is an attempt to establish molecular and cellular landmarks to understand how sensilla emerge from a population of undifferentiated cells.; Recently, the complete Drosophila OBP repertoire has been identified. Their expression pattern is not restricted to olfactory sensilla but is also seen in gustatory sensilla thus prompting a revision of their potential function in signal transduction. In chapter II, I will introduce a new member of the OBP family in the yellow fever mosquito A. aegypti. Aaeg-OBP10 is expressed in a sex and tissue specific pattern. But interestingly, Aaeg-OBP10 is expressed in appendages known to carry olfactory or gustatory sensilla. The developmental profile of Aaeg-OBP10 suggests this gene functions in an adult context.; The adult antenna of M. sexta derives from an antennal anlagen called imaginal disc. During the last instar larva the disc grows allometrically. Following the larval-pupal molt, it differentiates into the sensilla bearing adult antenna. A number of transcription factors and cell-cell communication proteins are responsible for the growth and patterning of limbs. In the third chapter, I present the temporal expression pattern of Distal-less and Notch. Both genes are involved in limb morphogenesis and neurogenesis. I will describe their temporal expression pattern during the post-embryonic development of the adult olfactory epithelium.; During development, genes encode proteins, dictating cell behaviors and ultimately defining the future organization of entire tissues. In chapter IV, I describe the cellular events occurring during adult neurogenesis in the moth M. sexta. I used a pupal-cuticle protein gene ( Msex-PCP) as an epidermal cell marker to visualize which cells follow which developmental program whether it is neuronal or epidermal. |
