The development of all multi-cellular organisms relies upon the perfect balance between cellular growth and differentiation to generate and maintain tissues and organs. We have investigated the molecular controls of germ cell fate decisions in the Caenorhabditis elegans germ line. Germ cells can either divide mitotically or enter the meiotic cell cycle to differentiate as either sperm or oocytes. Strikingly, these decisions were found to be controlled by a network of conserved RNA regulators (1, 2, 3). In particular, the switch from mitosis to meiosis requires the translational repressors GLD-1, FBF, and NOS-3, and the translational activator complex GLD-2 / GLD-3. GLD-2 is a multi-subunit cytoplasmic poly(A) polymerase that is presumed to interact with target mRNAs through the putative RNA binding protein GLD-3, a Bicaudal C protein family member.
gld-2 and
gld-3 are required for normal germ cell entry and progression through meiosis and for proper early embryogenesis (2, 4). However,
gld-3 has additional roles in other cell fate decisions independent of
gld-2. Maternal
gld-3 ensures germ cell survival and zygotic
gld-3 controls the sperm/oocyte switch (4). In order to study the role of
gld-3 in detail for these functions, we performed a yeast 2-hybrid screen to identify interacting proteins. We isolated a novel gene, tentatively named
gls-1 (germline survival defective-1), which we also found to be involved in regulating germ cell survival and embryonic development. GLS-1 binds to GLD-3 specifically in vitro and is expressed in the cytoplasm throughout germline development and associates with P granules. We will present our molecular and genetic work on characterizing
gls-1 deletion mutations. This study not only supports a role for
gls-1 in germ cell survival and early embryogenesis, but suggests additional roles for
gls-1 in the mitosis/meiosis and sperm/oocyte decisions as well.. (1) Eckmann et al.; (2004) Genetics 168,
pp147-60. (2) Eckmann et al.; (2002) Dev. Cell 3,
pp697-710. (3) Hansen et al.; (2004) Development 131,
pp93-104. (4) Wang et al.; (2002) Nature 419,
pp312-6.