A Functional Analysis of Calcium Channel painless and dTRPA1 in Germ Cell Migration in Drosophila Melanogaster

Abstract

Primitive embryonic gonad in Drosophila melanogaster consists primarily of two types of cells, Primordial Germ Cells (PGCs) and Somatic Gonadal Precursor cells (SGPs). While SGPs are stationary, PGCs undergo directed migration across the embryo. It is proposed and widely supported that the signaling ligand Hedgehog (Hh) plays a significant role in directed migration of the PGCs to the SGPs. The SGPs themselves synthesize Hh, in addition to several other genes involved in modulating range/strength of Hh signaling in germ cell migration. However, the germ cell autonomous factors and mechanisms that enable PGCs to receive and act upon the attractive signals emanating from the SGPs are unclear. Moreover, how this signaling event is eventually translated into directed motility to the correct location in the embryo is also unclear. This paper proposes that Painless, a Calcium channel, contributes to this particular aspect of germ cell migration and likely serves as one of the aforementioned cell autonomous factors. Recent studies have demonstrated that calcium channels including Painless and TRPA1, are involved in Drosophila nociception, signaled by the same Hh ligand. As painless is expressed in a germ cell-specific manner, we investigate the involvement and function of painless in the reception of signaling and migration of PGC’s.