Ανάπτυξη διαγονιδιακών συστημάτων για τον έλεγχο πληθυσμών βλαβερών εντόμων : καταστολή της έκφρασης του γονιδίου μιας αξονηματικής δυνείνης

Many insects heavily damage crops and forests or transmit deadly diseases to animals and humans. The Sterile Insect Technique (S.I.T) is a genetic method that can be used to successfully suppress economically important pest species. SIT involves mass production of the target pest species, sterilization by irradiation and release of sterilized insects. The need to sterilize the insects by irradiation causes a dramatic loss of competitive mating ability relative to wild type. The replacement of radiation-sterilization by a molecular genetic-sterilization method is an attractive option for the production of sterile insects. Herein we report the development of a transgenic system that suppresses the expression of b- heavy chain KL-5, part of the outer arm of axonemal dynein of Drosophila melanogaster, with the production of dsRNA under heat-shock. kl-5 gene is mapped on the Y chromosome and encodes a dynein polypeptide that is an essential functional component of the sperm flagellar axoneme. kl-5 gene is expressed only in primary spermatocytes in the testis and its null mutants exhibit immotile sperm. The production of dsRNA to silence kl-5 is effective, but could be improved. So we developed a new transgenic system in order to strictly regulate the suppression of kl-5 gene under a promoter activated in the absence of tetracycline. This system is based on the production of dsRNA upon the binding of transactivator tTA on the sequence of tetracycline operator (tetO). The expression of tTA is under the control of the promoter of hsp26 gene of Drosophila melanogaster that gives spermatocyte-specific expression. The aim of this project is the development of transgenic-sterile males of D. melanogaster with no other abnormalities in their physiology. This strain could be a model for a similar application in insect pest management.Many insects heavily damage crops and forests or transmit deadly diseases to animals and humans. The Sterile Insect Technique (S.I.T) is a genetic method that can be used to successfully suppress economically important pest species. SIT involves mass production of the target pest species, sterilization by irradiation and release of sterilized insects. The need to sterilize the insects by irradiation causes a dramatic loss of competitive mating ability relative to wild type. The replacement of radiation-sterilization by a molecular genetic-sterilization method is an attractive option for the production of sterile insects. Herein we report the development of a transgenic system that suppresses the expression of b- heavy chain KL-5, part of the outer arm of axonemal dynein of Drosophila melanogaster, with the production of dsRNA under heat-shock. kl-5 gene is mapped on the Y chromosome and encodes a dynein polypeptide that is an essential functional component of the sperm flagellar axoneme. kl-5 gene is expressed only in primary spermatocytes in the testis and its null mutants exhibit immotile sperm. The production of dsRNA to silence kl-5 is effective, but could be improved. So we developed a new transgenic system in order to strictly regulate the suppression of kl-5 gene under a promoter activated in the absence of tetracycline. This system is based on the production of dsRNA upon the binding of transactivator tTA on the sequence of tetracycline operator (tetO). The expression of tTA is under the control of the promoter of hsp26 gene of Drosophila melanogaster that gives spermatocyte-specific expression. The aim of this project is the development of transgenic-sterile males of D. melanogaster with no other abnormalities in their physiology. This strain could be a model for a similar application in insect pest management