View Program - 63rd Annual Drosophila Research Conference

The D. melanogaster protein-coding gene bag of marbles (bam) plays a key role in early male and female reproduction by forming complexes with partner proteins to promote differentiation in gametogenesis. A bam null mutant and a bam partial loss-of-function hypomorphic mutant result in sterility and reduced fertility, respectively. Like another germline gene, Sxl, bam genetically interacts with the endosymbiont Wolbachia, as Wolbachia rescues the reduced fertility of the hypomorphic mutant. Here, we explored the specificity of the bam Wolbachia interaction by combining an alanine scanning approach with phylogenetic sequence data to efficiently generate new mutants to test for Wolbachia rescue. We have generated several new mutants with reduced fertility in one of bam’s documented binding regions, highlighting the functional importance of certain residues for bam’s activity. All of these new reduced fertility mutants are rescued by Wolbachia in females. Additionally, we find that Wolbachia also rescues the reduced fertility of a bam transgenic allele in male D. melanogaster, revealing the first genetic interaction between Wolbachia and germline genes in males. Additional mutants in other documented binding regions of bam as well as bam RNAi knockdowns are currently being evaluated to further elucidate the specificity of the bam Wolbachia interaction. If Wolbachia rescue remains specific to this single binding region, it would suggest that the Wolbachia interaction occurs in this pathway of bam's function. Better understanding the nature of bam’s interaction with Wolbachia will allow us to evaluate hypotheses about the potential contribution of Wolbachia as a driver of bam’s rapid evolution in the D. melanogaster group.

Genetic interactions between new bag-of-marbles mutants and the endosymbiont bacteria Wolbachia in D. melanogaster