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| Author(s): |
Franciene Rabiço Oliveira
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2020-02-06 |
| Examining board members: |
Zila Luz Paulino Simoes;
Ana Maria Bonetti;
Ricardo Guelerman Pinheiro Ramos
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| Advisor: | Zila Luz Paulino Simoes |
| Abstract | |
The onset of embryonic development is unique and has its own characteristics, where each component is programmed to act in a precisely defined place and time. In its initial phase, the embryo has no zygotic transcription, being maintained by molecular components deposited by the mother during oogenesis. The transcriptional activation of the zygotic genome is coordinated with the degradation of maternally derived mRNAs, resulting in a change in the embryo transcriptional profile. Thus, during this transition, called materno-zygote (MZT), the zygote establishes control of its development. The degradation of maternal products occurs mainly by the joint action of Smaug and Zelda. In Drosophila melanogaster, zygotic transcription gradually increases from cycle 2 to cycle 13 of embryonic development. Zelda is a gene that plays an essential role in early embryogenesis. The homology, sequence of this gene and functional domains are highly conserved in the order Hymenoptera, as well as in other investigated species. Pilot experiments detected zelda expression early in the early stages of Apis mellifera embryonic development, which prompted the investigation of other equally important genes in the early stages of embryonic development. From RNAseq libraries we selected RpL32, tropoinin C type IIb, takeout, engrailed even-skipped, hairy, kruppel and oddskipped for expression analysis from oocyte (time zero, 0), 2 and 6 hours of development. For this purpose, primers were designed for both transcript forms, presplicing and post-splicing, as a way to validate transcription by the embryo. The results point to a synthesis activity of new transcripts in the first hour of embryonic development. To complement the findings and verify the mitotic cycles of that period, the nuclei of diploid embryos with 1 hour of development after laying were marked with DAPI in order to verify the mitotic cycles of this period. We observed at 1 hour of development, three cleavage nuclei, indicating that they went through two mitotic cycles, suggesting an asynchronous division. These findings strongly indicate that there may be zygotic gene expression in the early mitotic cycles of the A. mellifera embryo. Finally, the reconstruction of gene - protein interaction networks in early embryonic development was performed. The results indicate that several genes and proteins may be involved in the early stages of zygote activation. We believe that these results will certainly help to clarify the first steps of embryogenesis in this model organism, opening new and promising fields for studies in this area. (AU) | |
| FAPESP's process: | 17/18941-7 - Egg to embryo: analysis of the activation of early development of Apis mellifera |
| Grantee: | Franciene Rabiço Oliveira |
| Support Opportunities: | Scholarships in Brazil - Master |