Protein Domain : Chorion S16 IPR008450

Type	Family
Description	Correct eggshell formation relies on a complex series of events that relies on expression, cleavage and transport of various proteins at appropriate times. In Drosophila, the eggshell framework is laid down between the developing oocyte and the overlying follicle cells during late oogenesis. Five distinct layers are observed in Drosophila eggshells: the oocyte proximal vitelline membrane, a lipid wax layer, the inner chorion layer, the endochorion and exochorion layers [ ].The inner chorion layer is continuous and characterised by its periodic structure. Genes encoding chorion proteins are expressed from oocyte development stage 11 onwards. Chorion synthesis occurs during the last 5-6 hours of oogenesis and demands the production of large amounts of protein. Amplification of the two chorion gene clusters meets demand for large scale protein production and expression is precisely regulated through tight transcriptional control of the chorion genes. Chorion proteins may be described according to the times at which they are expressed in the follicular cells: developmentally early (s36, s38), middle (s19, s16) or late (s18, s15).This family consists of several examples of the Drosophila melanogaster specific chorion protein S16. The chorion genes of Drosophila are amplified in response to developmental signals in the follicle cells of the ovary [ ].
Short Name	Chorion_S16