Figure 2.

yl RNA expression in the germ line cells. (A) Whole-mount RNA in situ hybridization shows yl RNA is expressed in wild-type germ line cells and accumulates in the oocyte as early as region 2 in the germarium (g). Inset, Higher magnification of a germarium with yl RNA localized to the presumptive oocyte of region 2 and region 3 cystocytes. (B) yl RNA levels in wild-type ovaries increase in the nurse cells during stages 9 and 10. (C) In egl¹/egl¹mutant chambers, which have 16 nurse cells but no oocyte, yl RNA is still expressed but it is not localized to any of the cells. (D) Similar results are seen with a hypomorphic BicD allele [BicD^R29/Df(2)TW119], although some RNA accumulation in the most posterior cell is seen in very early stage chambers. (E) Staining is not seen in the yl null [Df(1)g^l/Df(1)KA9] control. (F) β-Galactosidase is detected in the germ line cells of a yl-lacZ transgenic ovary. The yl-lacZ reporter construct contains the first 400 bp upstream of the yl transcription start site.