Self-renewing stem cells are pools of undifferentiated cells, which are
maintained in cellular niche environments by distinct tissue-specific
signalling pathways. In Drosophila melanogaster, female germline stem cells
(GSCs) are maintained in a somatic niche of the gonads by BMP signalling. Here
we report a novel function of the Drosophila kinase Bällchen (BALL), showing
that its cell autonomous role is to maintain the self-renewing capacity of
female GSCs independent of BMP signalling. ball mutant GSCs are eliminated
from the niche and subsequently differentiate into mature eggs, indicating
that BALL is largely dispensable for differentiation. Similar to female GSCs,
BALL is required to maintain self-renewal of male GSCs, suggesting a tissue
independent requirement of BALL for self-renewal of germline stem cells