Makorin 1 controls embryonic patterning by alleviating Bruno-mediated repression of oskar translation

ABSTRACT: Makorins are an evolutionary conserved family of proteins that contain C3H-type zinc finger modules and a RING E3 ubiquitin ligase domain. Previous analysis indicated a maternal role for Makorin 1 (Mkrn1) in Drosophila embryonic patterning and germ cell specification, but the underlying mechanism has remained elusive. Here, we show that Mkrn1 is specifically required for translational activation of oskar, which encodes a critical regulator of axis specification and germ plasm assembly. We demonstrate that Mkrn1 interacts with poly(A) binding protein (pAbp) and specifically binds osk 3’ UTR adjacent to A-rich sequences. The binding of Mkrn1 to osk 3’UTR occurs in a region that overlaps with Bruno responsive elements (BRE), previously shown to have a dual role in regulating osk translation. We observe an increased association of the translational repressor Bruno (Bru) with osk mRNA upon depletion of Mkrn1, implying that both proteins compete with each other for osk binding. Consistently, reducing Bru dosage is sufficient to partially rescue osk translation and the embryonic lethality associated with Mkrn1 alteration. Thus, we conclude that Mkrn1 controls embryonic patterning and germ cell formation by specifically activating osk translation via displacing Bru from its 3’ UTR

INSTRUMENT(S): Q Exactive

ORGANISM(S): Drosophila Melanogaster (fruit Fly)

TISSUE(S): Cell Culture

SUBMITTER: Annabelle Dold  

LAB HEAD: Jean-Yves Roignant

PROVIDER: PXD011802 | Pride | 2020-01-29

REPOSITORIES: Pride