PT  - JOURNAL ARTICLE
AU  - Mehmet Ilyas Cosacak
AU  - Hatice Yiğit
AU  - Bünyamin Akgül
TI  - Re-arrangements in the cytoplasmic distribution of small RNAs following the maternal-to-zygotic transition in <em>Drosophila</em> embryos
AID  - 10.1101/224626
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 224626
4099  - http://biorxiv.org/content/early/2017/11/25/224626.short
4100  - http://biorxiv.org/content/early/2017/11/25/224626.full
AB  - Small RNAs are known to regulate gene expression during early development. However, the dynamics of interaction between small RNAs and polysomes during this process is largely unknown. 0-1h and 7-8h Drosophila embryos were fractionated on sucrose density gradients into four fractions based on A254 reading (1) translationally inactive messengerribonucleoprotein (mRNP); (2) 60S; (3) monosome; and (4) polysome. Comparative analysis of deep-sequencing reads from fractionated and un-fractionated 0-1h and 8-h embryos revealed development-specific co-sedimentation pattern of small RNAs with the cellular translation machinery. Although most miRNAs did not have a specific preference for any state of the translational machinery, we detected fraction-specific enrichment of some miRNAs such as miR-1-3p, -184-39, 5-5p and 263-5p. More interestingly, we observed dysregulation of a subset of miRNAs in fractionated embryos despite no measurable difference in their amount in unfractionated embryos. Transposon-derived endosiRNAs are over-expressed in 7-8h embryos and are associated mainly with the mRNP fraction. However, transposon-derived piRNAs, which are more abundant in 0-1h embryos, co-sediment primarily with the polysome fractions. These results suggest that there appears to be a complex interplay among the small RNAs with respect to their polysome-cosedimention pattern during early development in Drosophila.