Glycosylation is essential for the normal development of multicellular organisms, including C. elegans. For example, in worm, mutations in the sqv genes, which are involved in proteoglycan biosynthesis, result in maternal effect lethality or a squashed vulva (Sqv) phenotype. In addition, we have previously reported that a deletion in
gna-2, which catalyses synthesis of the glycoconjugate building block, UDP-GlcNAc, is maternal effect lethal and results in a multinucleated phenotype. We have now characterised the
gna-2(
qa705) phenotype in greater detail. Sperm asters and spindles are greatly reduced in
gna-2(
qa705). While some
gna-2(
qa705) embryos undergo cytokinesis, cell division never keeps up with nuclear division, resulting in a terminal, multinucleated phenotype.
gna-2(
qa705) fails to localise PGL-1, PIE-1 and PAR-3 correctly and is osmotically defective, identifying
gna-2(
qa705) as a novel pod gene. In utero microscopy of a
gna-2(
qa705), histone H2B::GFP strain demonstrates that meiosis I occurs, but the resultant polar body is not extruded. Meiosis II has never been seen, which is consistent with the common "3 pronuclei" phenotype seen in live embryos carrying the histone H2B::GFP or in fixed embryos stained with Hoechst. Since lectins bind glycoconjugates, we stained N2 and
gna-2(
qa705) embryos with fluorescently-labeled WGA, STA, LEA, SBA and SNA. Eggshell lectin staining was decreased in
gna-2(
qa705). In N2, WGA-FITC also binds to cortical patches that are coincident with meiosis, the first stage at which we detect a defect in
gna-2(
qa705). Interestingly, these patches are absent in
gna-2(
qa705). Injection with an extrachromosomal array encoding a GNA-2::GFP fusion demonstrates rescue of
gna-2(
qa705), but very low GFP expression. The greatest intensity of germline signal is seen in the proximal gonad and in very early embryos. Rescued lines are also Him, which may reflect a partial rescue of the meiotic defect. Our working hypothesis is that UDP-GlcNAc is necessary for the synthesis of a plasma membrane or extracellular matrix glycoconjugate that facilitates meiosis II and localisation of polarity determinants. Possible mechanisms include a structural role, where the glycoconjugate is involved in anchoring the meiotic spindle and polarity determinants or a non-structural role, for example by altering residency time of cell signaling molecules. Destruction of signaling molecules, or their downstream effectors, by the APC may allow progression of meiosis II and establishment/maintenance of polarity, which could explain the similarity of the
gna-2(
qa705) phenotype to that of
cul-2 (ubiquitin ligase) and
pod-3-6(APC subunits).