From Oocyte to Fertilizable Egg

Cragle, Chad E.; MacNicol, Angus M.

doi:10.1002/9781118492833.ch3

Cited by 5 publications

(6 citation statements)

References 171 publications

(168 reference statements)

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“…For example, stored Xenopus maternal mRNAs are translationally repressed due to their association with general repressor proteins such as FRGY2, XP54 (DDX6), and RAP55 (Colegrove-Otero et al 2005a; Minshall et al 2001, 2007; Tanaka et al 2006, 2014; Tafuri and Wolffe 1993; Ranjan et al 1993; Deschamps et al 1992). A comprehensive discussion of the RNA-binding proteins that mediate general translational repression in Xenopus oocytes and embryos is beyond the scope of this review (see Cragle and MacNichols for a thorough discussion (Cragle and MacNicol 2014a)). However, the following section will present a brief overview of the mechanisms of translation control that operate during Xenopus oocyte maturation and early cleavage stages with an emphasis on what is known about the functional sequence elements and their cognate binding proteins.…”

Section: 5 Translational Control Mechanisms Operating During Xenopumentioning

confidence: 99%

“…The regulated addition of adenylates to the 3′ end of maternal mRNAs, referred to as poly(A) tail lengthening or polyadenylation, is a mechanism used to control the translational activation of specific mRNAs during oocyte maturation (Cragle and MacNicol 2014a; Standart and Minshall 2008; Richter and Lasko 2011). The majority of eukaryotic mRNAs are cleaved and polyadenylated in the nucleus in two coupled reactions that recognize the conserved 5′-AAUAAA-3′ present in their 3′ untranslated regions (UTRs).…”

Section: 5 Translational Control Mechanisms Operating During Xenopumentioning

confidence: 99%

“…In Xenopus , the Cripto-1 mRNA is uniformly distributed throughout the egg and all embryonic cells. The Cripto-1 protein is only produced in animal cells of embryos after fertilization, but not vegetal cells (Cragle and MacNicol 2014a). Differential accumulation of the Cripto-1 protein in Xenopus embryos is due to the spatially regulated translation of the Cripto-1 mRNA.…”

Section: Fig 21mentioning

confidence: 99%

“…In response to the hormone progesterone, they are released from meiotic arrest (oocyte maturation), complete meiosis, and become fertilizable eggs released by the mother. During oocyte maturation some localized mRNAs are released from their storage forms and are translated into proteins (Cragle and MacNicol 2014a; Standart and Minshall 2008). This translation contributes to the conversion of the mRNA asymmetries formed in the oocyte to protein asymmetries present in the egg that will be inherited by cells of the embryo.…”

Section: 1 Introductionmentioning

confidence: 99%

“…Some maternal mRNAs encode cell cycle proteins and fundamental cell structural proteins needed to drive the first rapid cell divisions in the fertilized embryo. Thus the regulated translation of maternal mRNAs prepares the embryo for the rapid cell divisions that immediately follow fertilization and generates proteins that guide formation of the vertebrate body plan (Heasman 2006a; Cragle and MacNicol 2014a; Gray and Wickens 1998; Richter and Lasko 2011). …”

Section: 1 Introductionmentioning

confidence: 99%

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Controlling the Messenger: Regulated Translation of Maternal mRNAs in Xenopus laevis Development

Sheets

Fox

Dowdle

et al. 2016

Advances in Experimental Medicine and Biology

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The selective translation of maternal mRNAs encoding cell-fate determinants drives the earliest decisions of embryogenesis that establish the vertebrate body plan. This chapter will discuss studies in Xenopus laevis that provide insights into mechanisms underlying this translational control. Xenopus has been a powerful model organism for many discoveries relevant to the translational control of maternal mRNAs because of the large size of its oocytes and eggs that allow for microinjection of molecules and the relative ease of manipulating the oocyte to egg transition (maturation) and fertilization in culture. Consequently, many key studies have focused on the expression of maternal mRNAs during the oocyte to egg transition (the meiotic cell cycle) and the rapid cell divisions immediately following fertilization. This research has made seminal contributions to our understanding of translational regulatory mechanisms, but while some of the mRNAs under consideration at these stages encode cell-fate determinants, many encode cell cycle regulatory proteins that drive these early cell cycles. In contrast, while maternal mRNAs encoding key developmental (i.e., cell-fate) regulators that function after the first cleavage stages may exploit aspects of these foundational mechanisms, studies reveal that these mRNAs must also rely on distinct and, as of yet, incompletely understood mechanisms. These findings are logical because the functions of such developmental regulatory proteins have requirements distinct from cell cycle regulators, including becoming relevant only after fertilization and then only in specific cells of the embryo. Indeed, key maternal cell-fate determinants must be made available in exquisitely precise amounts (usually low), only at specific times and in specific cells during embryogenesis. To provide an appreciation for the regulation of maternal cell-fate determinant expression, an overview of the maternal phase of Xenopus embryogenesis will be presented. This section will be followed by a review of translational mechanisms operating in oocytes, eggs, and early cleavage-stage embryos and conclude with a discussion of how the regulation of key maternal cell-fate determinants at the level of translation functions in Xenopus embryogenesis. A key theme is that the molecular asymmetries critical for forming the body axes are established and further elaborated upon by the selective temporal and spatial regulation of maternal mRNA translation.

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Section: 5 Translational Control Mechanisms Operating During Xenopumentioning

confidence: 99%

Section: 5 Translational Control Mechanisms Operating During Xenopumentioning

confidence: 99%

Section: Fig 21mentioning

confidence: 99%

Section: 1 Introductionmentioning

confidence: 99%

Section: 1 Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Controlling the Messenger: Regulated Translation of Maternal mRNAs in Xenopus laevis Development

Sheets

Fox

Dowdle

et al. 2016

Advances in Experimental Medicine and Biology

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Phosphorylation Dynamics Dominate the Regulated Proteome during Early Xenopus Development

Peuchen

Cox

Sun

et al. 2017

Sci Rep

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The earliest stages of animal development are largely controlled by changes in protein phosphorylation mediated by signaling pathways and cyclin-dependent kinases. In order to decipher these complex networks and to discover new aspects of regulation by this post-translational modification, we undertook an analysis of the X. laevis phosphoproteome at seven developmental stages beginning with stage VI oocytes and ending with two-cell embryos. Concurrent measurement of the proteome and phosphoproteome enabled measurement of phosphosite occupancy as a function of developmental stage. We observed little change in protein expression levels during this period. We detected the expected phosphorylation of MAP kinases, translational regulatory proteins, and subunits of APC/C that validate the accuracy of our measurements. We find that more than half the identified proteins possess multiple sites of phosphorylation that are often clustered, where kinases work together in a hierarchical manner to create stretches of phosphorylated residues, which may be a means to amplify signals or stabilize a particular protein conformation. Conversely, other proteins have opposing sites of phosphorylation that seemingly reflect distinct changes in activity during this developmental timeline.

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eIF4E-binding proteins: new factors, new locations, new roles

Kamenska

Simpson

Standart

2014

Biochemical Society Transactions

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The cap-binding translation initiation factor eIF4E (eukaryotic initiation factor 4E) is central to protein synthesis in eukaryotes. As an integral component of eIF4F, a complex also containing the large bridging factor eIF4G and eIF4A RNA helicase, eIF4E enables the recruitment of the small ribosomal subunit to the 5' end of mRNAs. The interaction between eIF4E and eIF4G via a YXXXXLϕ motif is regulated by small eIF4E-binding proteins, 4E-BPs, which use the same sequence to competitively bind eIF4E thereby inhibiting cap-dependent translation. Additional eIF4E-binding proteins have been identified in the last 10-15 years, characterized by the YXXXXLϕ motif, and by interactions (many of which remain to be detailed) with RNA-binding proteins, or other factors in complexes that recognize the specific mRNAs. In the present article, we focus on the metazoan 4E-T (4E-transporter)/Cup family of eIF4E-binding proteins, and also discuss very recent examples in yeast, fruitflies and humans, some of which predictably inhibit translation, while others may result in mRNA decay or even enhance translation; altogether considerably expanding our understanding of the roles of eIF4E-binding proteins in gene expression regulation.

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From Oocyte to Fertilizable Egg

Cited by 5 publications

References 171 publications

Controlling the Messenger: Regulated Translation of Maternal mRNAs in Xenopus laevis Development

Controlling the Messenger: Regulated Translation of Maternal mRNAs in Xenopus laevis Development

Phosphorylation Dynamics Dominate the Regulated Proteome during Early Xenopus Development

eIF4E-binding proteins: new factors, new locations, new roles

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