TRANSLATIONAL CONTROL MEDIATED BY DIFFERENT DOMAINS OF ME31B IN Drosophila

VILARDO E; RIVERA POMAR R; LAYANA C

Parana

Congreso; LIV Reunion Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2018

SAIB

Development of an organism implies regulation of gene expression at several levels. The eukaryotic initiation factor 4E (eIF4E) is a key factorinvolved in mRNA metabolism. D. melanogaster genome encodes 8 eIF4E isoforms. The canonical isoform, eIF4E-1, plays a role in translationin the formation of P-bodies, and is a translational repressor in oogenesis when it interacts with Me31B. While eIF4E-3 is expressed in testis andcontrol translation initiation during male germ line development. d4E-HP (4E-8) is a translational repressor in the embryo and interacts withBicoid to inhibit the translation of caudal mRNA. Previous results of our laboratory showed that Me31B interacts with eIF4E-1 and eIF4E-3,both in the yeast two-hybrid system and in S2 cells by FRET. We demonstrate that Me31B is also expressed during spermatogenesis and colocalize with eIF4E-3 in the male germ cells.Here we have further investigated the molecular interaction of Me31B and eIF4Es using two-hybridassay. We generated Me31B truncated proteins and point mutation by site directed mutagenesis. Our results indicate that the binding sites ofMe31B and eIF4E-1 or eIF4E-3 are located in a different domain inside the Me31B sequences. Specifically eI4E1 binds to D1 domain (Me31B1-96) while eIF4E3 binds to D2 domain (Me31B366-459). We also showed that the 4E mutants that delocalize the PBs (eIF4E-1W117A y eIF4E-3F103A)are not able to interact with Me31B.These results suggest that the development of the germ line requires the mRNA silencing mediated by theinteraction of specific factors depending on whether it is the female or the male, through differential domains of interaction