With the progress in our understanding of germ cell development, there is an emerging need to investigate the mechanisms of mRNA translation functioning in these cells. Indeed, posttranscriptional regulations of gene expression drive the most important transitions of the germ cell life cycle. Here we describe a strategy to measure mRNA translation in the oocyte, taking advantage of an approach originally developed to identify the transcriptome of a subgroup of cells in a complex cell mixture. This technique takes advantage of the "RiboTag" approach to express an HA-tag on the large ribosomal subunit of the ribosomes in the oocyte. Immunoprecipitation of the extracts followed by qPCR or RNAseq is used to identify mRNAs actively translated.

Inference can be viewed as a search through a space of inference rules. Backward and forward inference differ in the direction of the search: backward inference searches from goals to ground assertions; forward inference searches from ground assertions to goals. This paper describes an inference procedure, called bi-directional inference, which limits the number of inference rules searched. Bi-directional inference results from the interaction between forward and backward inference and loosely corresponds to bi-directional search. We show through an example that, when used throughout a session of related tasks, bi-directional inference sets up a conversational context and prunes the search through the space of inference rules by ignoring rules which are not relevant to that context.

Meiotic progression requires exquisitely coordinated translation of maternal messenger (m)RNA that has accumulated during oocyte growth. A major regulator of this program is the cytoplasmic polyadenylation element binding protein 1 (CPEB1). However, the temporal pattern of translation at different meiotic stages indicates the function of additional RNA binding proteins (RBPs). Here, we report that deleted in azoospermia-like (DAZL) cooperates with CPEB1 to regulate maternal mRNA translation. Using a strategy that monitors ribosome loading onto endogenous mRNAs and a prototypic translation target, we show that ribosome loading is induced in a DAZL- and CPEB1-dependent manner, as the oocyte reenters meiosis. Depletion of the two RBPs from oocytes and mutagenesis of the 3' untranslated regions (UTRs) demonstrate that both RBPs interact with the Tex19.1 3' UTR and cooperate in translation activation of this mRNA. We observed a synergism between DAZL and cytoplasmic polyadenylation elements (CPEs) in the translation pattern of maternal mRNAs when using a genome-wide analysis. Mechanistically, the number of DAZL proteins loaded onto the mRNA and the characteristics of the CPE might define the degree of cooperation between the two RBPs in activating translation and meiotic progression.