Proteomic Analysis of Mouse Oocytes Reveals 28 Candidate Factors of the “Reprogrammome”

Abstract

The oocyte is the only cell of the body that can reprogram transplanted somatic nuclei and sets the gold standard for all reprogramming methods. Therefore, an in-depth characterization of its proteome holds promise to advance our understanding of reprogramming and germ cell biology. To date, limitations on oocyte numbers and proteomic technology have impeded this task, and the search for reprogramming factors has been conducted in embryonic stem (ES) cells instead. Here, we present the proteome of metaphase II mouse oocytes to a depth of 3699 proteins, which substantially extends the number of proteins identified until now in mouse oocytes and is comparable by size to the proteome of undifferentiated mouse ES cells. Twenty-eight oocyte proteins, also detected in ES cells, match the criteria of our multilevel approach to screen for reprogramming factors, namely nuclear localization, chromatin modification, and catalytic activity. Our oocyte proteome catalog thus advances the definition of the "reprogrammome", the set of molecules--proteins, RNAs, lipids, and small molecules--that enable reprogramming.

Setd1b, encoding a histone 3 lysine 4 methyltransferase, is a maternal effect gene required for the oogenic gene expression program

“…In mouse oocytes, mRNAs for all six Set1/Trithorax-type members, Setd1a, Setd1b and Mll1-4, are expressed (Kageyama et al, 2007;Andreu-Vieyra et al, 2010;Pfeiffer et al, 2011;Bledau et al, 2014;Aoshima et al, 2015). To date, we have conditionally mutated Mll1, Mll2, Setd1a and Setd1b using Gdf9-iCre to establish that only oocyte-specific deletion of Setd1b and Mll2 perturb fertility (Andreu-Vieyra et al, 2010;Bledau et al, 2014; this paper; and A.K., Q.Z., K.A.…”

Maternal age effect on mouse oocytes: new biological insight from proteomic analysis

“…PAPOLA is also one of the 118 proteins with no detected cognate mRNA, together with HDAC1/2 (member of the 'reprogrammome'; Supplementary Fig. 3, see section on supplementary data given at the end of this article; Pfeiffer et al 2011), suggesting that the amount of enzyme for these two factors may not be replenished without de novo transcription. We speculate that this might be a fatal hurdle for SCNT embryos because de novo transcription of the Papola gene is dependent on prior nuclear reprogramming, which is known to be inefficient.…”

Identification and Characterization of an Oocyte Factor Required for Porcine Nuclear Reprogramming

“…During the past decades, several approaches analyzing the protein composition of oocytes have been conducted to obtain the proteome signatures of Xenopus, bovine, pig, and mouse oocytes (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Calvert et al (15) identified eight highly abundant heat shock proteins and related chaperones in the mature mouse egg by two-dimensional difference gel electrophoresis (DIGE).…”