Axis formation during Drosophila oogenesis

Recent advances shed light on the cellular processes that cooperate during oogenesis to produce a fully patterned egg, containing all the maternal inf ormation required for embryonic development. Progress has been made in defi ning the early steps in oocyte specification and it has been shown that pro gression of oogenesis is controlled by a meiotic checkpoint and requires ac tive maintenance of the oocyte cell fate. The function of Gurken signalling in patterning the dorsal-ventral axis later in oogenesis is better underst ood. Anteroior-posterior patterning of the embryo requires activities of bi coid and oskar mRNAs, localised within the oocyte. A microtubule motor, Kin esin, is directly implicated in localisation of oskar mRNA to the posterior pole of the oocyte.