Bam/Bgcn forms a multiple protein complex of Brat, Mei-P26 and AGO1 proteins and negatively regulate expression of dMyc cell growth regulator through dMyc mRNA

Abstract

In the Drosophila germ line, Bag of Marbles (Bam) is the major differentiation factor required for differentiation of Germ line stem cell (GSC) to cystoblast (CB) and shows it’s high expression in the differentiating daughter cells. Another factor diminutive (dMyc), the homolog of the human c-myc oncogene, an important regulator of cell growth is highly expressed in self renewal stem cells but downregulated in differentiating daughters cystoblasts and 16-cell cysts stage. The underlying mechanism of downregulation of dMyc in 16-cell cysts stage and CB is unknown. These findings demonstrates that Bam forms multiple complex with TRIM–NHL domain containing factors  Brat, Mei-P26 and miRNA pathway component AGO1 and represses  dMyc mRNA through its microRNA sites containing 201-400 bp region of Myc 3’UTR in differentiating daughter cells and cystoblasts.