Analysis of the transcription fator Zelda along the development of Apis mellifera
Franciene Rabiço Oliveira, Franciene Rabiço Oliveira , Zilá Luz Paulino Simões
Departamento de Genética, Universidade de São Paulo, Ribeirão Preto, Brazil; Departamento de Genética, Universidade de São Paulo, Ribeirão Preto, Brasil ; Departamento de Biologia, Universidade de São Paulo, Ribeirão Preto, Brasil
As in the majority of organisms, in Apis mellifera oogenesis maternal products synthesized in the ovary and fat body cells are loaded into developing oocytes. Many of these products control the early development and maintain the embryo prior to zygote genome activation. Among these molecules, we find zelda transcripts, a pioneer gene in embryonic development. Zelda is involved in zygote genome activation and regulation of later stages of embryonic development. To check zelda expression in A. mellifera we analyzed ovaries, brain ganglion, and fat body, performing qPCR analyses of queens, and workers in different developmental stages and conditions. The expression profiles of zelda indicate that this gene is involved in the reproductive state of ovaries, but does not show caste-specific patterns. Active ovaries of workers showed higher levels of zelda transcripts compared to inactive ovaries of workers and the active ovaries of queens. Expression of zelda fluctuates considerably in the first six hours of embryogenesis, with the highest peak of expression in the interval between 0-1h after egg laying. We also investigated the effect of queen’s presence on zelda expression profiles, comparing queenright and queenless workers over 28 days. High levels of zelda were found ten days after worker emergency and on day 24. Considering all results together, we suggest a higher reproductive plasticity at these stages. Lastly, transcripts of zelda were also found in RNA seq libraries from different tissues and castes, suggesting that zelda might play a role in late development and adult phase. Thus, our results suggest that the action of Zelda goes beyond the control of maternal-zygotic transition and that this transcription factor plays a role in the maintenance of different tissues throughout A. mellifera development.