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Updated: May 13, 2026
Maintenance of a Drosophila melanogaster Population Cage
Published on: March 15, 2016
miR-34 is maternally inherited in Drosophila melanogaster and Danio rerio
Kartik Soni1, Ashwani Choudhary, Ashok Patowary
1CSIR-Institute of Genomics and Integrative Biology, Delhi 110 007, India, Ambedkar Centre for Biomedical Research, Delhi University, Delhi 110007, India.
Abstract:
MicroRNAs (miRNAs) are small, endogenous, regulatory RNA molecules that can bind to partially complementary regions on target messenger RNAs and impede their expression or translation. We rationalized that miRNAs, being localized to the cytoplasm, will be maternally inherited during fertilization and may play a role in early development. Although Dicer is known to be essential for the transition from single-celled zygote to two-cell embryo, a direct role for miRNAs has not yet been demonstrated. We identified miRNAs with targets in zygotically expressed transcripts in Drosophila using a combination of transcriptome analysis and miRNA target prediction. We experimentally established that Drosophila miRNA dme-miR-34, the fly homologue of the cancer-related mammalian miRNA miR-34, involved in somatic-cell reprogramming and having critical role in early neuronal differentiation, is present in Drosophila embryos before initiation of zygotic transcription. We also show that the Drosophila miR-34 is dependent on maternal Dicer-1 for its expression in oocytes. Further, we show that miR-34 is also abundant in unfertilized oocytes of zebrafish. Its temporal expression profile during early development showed abundant expression in unfertilized oocytes that gradually decreased by 5 days post-fertilization (dpf). We find that knocking down the maternal, but not the zygotic, miR-34 led to developmental defects in the neuronal system during early embryonic development in zebrafish. Here, we report for the first time, the maternal inheritance of an miRNA involved in development of the neuronal system in a vertebrate model system.
Insights
Maternally inherited microRNAs (miRNAs) play a crucial role in early development. This study demonstrates that maternal miR-34 is essential for neuronal system development in zebrafish embryos.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- MicroRNAs (miRNAs) are small regulatory RNA molecules impacting gene expression.
- Maternal inheritance of cytoplasmic factors, including miRNAs, is crucial for early embryonic development.
- The role of miRNAs in early vertebrate development, particularly in the nervous system, remains largely unexplored.
Purpose of the Study:
- To investigate the role of maternally inherited microRNAs in early embryonic development.
- To identify specific miRNAs and their targets involved in zygotic gene expression.
- To determine the function of miR-34 in the development of the neuronal system in a vertebrate model.
Main Methods:
- Transcriptome analysis and miRNA target prediction in Drosophila.
- Experimental validation of miRNA presence and dependence on maternal Dicer-1 in Drosophila.
- Temporal expression profiling of miR-34 in zebrafish oocytes and embryos.
- Knockdown experiments targeting maternal and zygotic miR-34 in zebrafish.
Main Results:
- Drosophila miRNA dme-miR-34, homologous to mammalian miR-34, is present before zygotic transcription and depends on maternal Dicer-1.
- miR-34 is abundant in unfertilized zebrafish oocytes and decreases post-fertilization.
- Knockdown of maternal miR-34, but not zygotic miR-34, causes developmental defects in the zebrafish neuronal system.
Conclusions:
- Maternal inheritance of microRNAs is critical for early embryonic development.
- miR-34 is maternally inherited and essential for the proper development of the neuronal system in zebrafish.
- This study provides the first evidence of a maternally inherited miRNA regulating neuronal development in a vertebrate.
