Mouse aging oocyte proteome comparison

Here we asked if oocyte proteomes are representative of the transcriptomes, how the abundance of specific genes’ mRNA and protein responds to maternal aging, and if oocyte aging presents the features characteristic of somatic aging. To address these questions on the proteomic level, we employed stable isotope labeling of amino acids in cell culture (SILAC; Geiger et al. 2011) as the method of choice, and performed a SILAC screen of mouse metaphase II (MII) oocytes superovulated at 3, 8+-1 and 58+-10 weeks of maternal age, which correspond to pre-puberty, mature age and climacterium, respectively. We used heavy F9 embryonic carcinoma (EC) cells as internal or "Spike-in" standard for the quantification of oocytes proteins because in contrast to the oocytes they can easily be cultured feeder-free, have stem cell properties and should harbor the majority of all oocyte proteins (although with different relative abundances). The SILAC screen was conducted in parallel with conventional microarray analysis to compare the concordance of protein and transcript levels in these oocytes. Associated microarray data have been deposited to NCBI GEO with accession number GSE42959.