Smaug (protein)

Smaug is a RNA-binding protein in Drosophila that helps in maternal to zygotic transition (MZT).

[5] The MZT ends with the midblastula transition (MBT), which is defined as the first developmental event in Drosophila that depends on zygotic mRNA.

[6] In Drosophila, the initial developmental events are controlled by maternal mRNAs like Hsp83, nanos, string, Pgc, and cyclin B mRNA.

Smaug is expected to play a role in expression of three miRNAs – miR-3, miR-6, miR-309 and miR-286 during MZT in Drosophila.

Smaug also binds to 3′ untranslated region (UTR) elements known as SMG response elements (SREs) on nanos mRNA[13][14] and represses its expression by recruiting a protein called Cup (an eIF4E-binding protein that blocks the binding of eIF4G to eIF4E).