GLP-1 is a Notch family receptor that is important in cell fate specification of the early Caenorhabditis elegans embryo. The translation of
glp-1 is spatially and temporally regulated through sequences in its 3 untranslated region (UTR). GLP-1 protein is translated mostly in anterior cells beginning at the two-cell stage continuing to the 16-cell stage. Several regulatory regions of
glp-1 3 UTR have been identified. There is one region at the 3 end of the UTR that is essential for translational repression in oocytes and 1-cell embryos. This region is called the oocyte control region (OCR). Another region is essential for the special regulation of GLP-1 translation. This GLP-1 localization region (GLR) is both necessary and sufficient for the spatial regulation of GLP-1. The GLR contains both an element necessary for translational repression in posterior cells and another element required for activation of translation in the anterior cells. Our hypothesis is that RNA binding proteins interact with the 3' UTR of
glp-1 controlling its translation, and that these proteins contribute to anterior-posterior patterning. In order to identify these proteins, we have performed RNA precipitations to identify proteins that bind the regulatory regions of the
glp-1 3 UTR. These RNA precipitations have isolated two bands which can be visualized by UV crosslinking,
p58 and
p30, that bind with specificity to a region within the GLR that is required for repression of translation in posterior cells. These two bands are not able to crosslink to a probe containing a 5-nucleotide mutation within this repression region. Furthermore, these bands cannot be competed off with an excess of this same mutation. We conclude that
p58 and
p30 are RNA binding proteins that may be involved in the translational repression of GLP-1 expression in posterior cells. We intend to isolate enough of these polypeptides to identify them using mass spectrometry.