Eyes absent in the cockroach panoistic ovaries regulates proliferation and differentiation through ecdysone signalling

Eyes absent (Eya), is a protein structurally conserved from hydrozoans to humans, for which two basic roles have been reported: it can act as a transcription cofactor and as a protein tyrosine phosphatase. Eya was discovered in the fly Drosophila melanogaster in relation to its function in eye development, and the same function was later reported in other insects. Eya is also involved in insect oogenesis, although studies in this sense are limited to D. melanogaster, which has meroistic ovaries, and where eya mutations abolish gonad formation. In the present work we studied the function of eya in the panoistic ovary of the cockroach Blattella germanica. We show that eya is essential for correct development of panoistic ovaries. In B. germanica, eya acts at different level and in a distinct way in the germarium and the vitellarium. In the germarium, eya contributes to maintain the correct number of somatic and germinal cells by regulating the expression of steroidogenic genes in the ovary. In the vitellarium, eya facilitates follicle cells proliferation and contributes to regulate the cell program, in the context of basal ovarian follicle maturation. Thus, eya-depleted females of B. germanica arrest the growth and maturation of basal ovarian follicles and become sterile.We thank the financial support from the Ministry of Science and Innovation, Spain for grants BFU2011-22404 and CGL2016-76011-R that also received financial assistance from the European Fund Economic and Regional Development (FEDER) And from the Catalan Regional Government (grant 2017 SGR 1030). PI is received the financial support from Apoyo al Retorno de Investigadores desde el Extranjero program (Convocatoria 2013, 821320046, PAI, CONICYT)