The poly(rC)-binding protein αCP2 is a noncanonical factor in <i>X. laevis</i> cytoplasmic polyadenylation

The Exon Junction Complex (EJC) plays a critical role in multiple posttranscriptional events, including RNA subcellular localization, nonsense-mediated decay (NMD), and translation. We previously reported that knockdown of the EJC core component Eukaryotic initiation factor 4a3 (Eif4a3) results in full-body paralysis of embryos of the frog, Xenopus laevis. Here, we explore the cellular and molecular mechanisms underlying this phenotype. We find that cultured muscle cells derived from Eif4a3 morphants do not contract, and fail to undergo calcium-dependent calcium release in response to electrical stimulation or treatment with caffeine. We show that ryr transcripts are incorrectly spliced in Eif4a3 morphants, and demonstrate that inhibition of Xenopus Ryanodine receptor (Ryr) function similarly results in embryonic paralysis. These results suggest that the EJC mediates muscle cell function via regulation of pre-mRNA splicing during early vertebrate embryogenesis.

show abstract

“…RNA co-immunoprecipitation assays were performed as described (Vishnu et al, 2011). Precipitated RNA was purified by RNA-Bee (Tel-Test, Inc.).…”

Section: Methodsmentioning

confidence: 99%

Eif4a3 is required for accurate splicing of the Xenopus laevis ryanodine receptor pre-mRNA

Haremaki

Weinstein

2012

Developmental Biology

View full text Add to dashboard Cite

show abstract

“…Most of the mRNAs targeted by cytoplasmic polyadenylation in oocytes and early embryos are directly involved in meiosis and/or mitosis . In all cases in which this was examined, cytoplasmic polyadenylation in Xenopus requires the poly(A) signal that is also used for nuclear polyadenylation . In addition, specific sequence elements in the 3′ untranslated region are required.…”

Section: Cytoplasmic Polyadenylation Of Mrnas In Germ Cells and Embryosmentioning

confidence: 99%

“…The second embryonic CPE in Xenopus was found to be a stretch of cytidine residues and called the C‐CPE . Cytoplasmic polyadenylation by the C‐CPE also requires a poly(A) signal and the element is bound by PCBP2 (αCP2, hnRNP‐E2), which is exclusively cytoplasmic in Xenopus oocytes .…”

Section: Cytoplasmic Polyadenylation Of Mrnas In Germ Cells and Embryosmentioning

confidence: 99%

See 1 more Smart Citation

Specificity factors in cytoplasmic polyadenylation

2013

View full text Add to dashboard Cite

Poly(A) tail elongation after export of an messenger RNA (mRNA) to the cytoplasm is called cytoplasmic polyadenylation. It was first discovered in oocytes and embryos, where it has roles in meiosis and development. In recent years, however, has been implicated in many other processes, including synaptic plasticity and mitosis. This review aims to introduce cytoplasmic polyadenylation with an emphasis on the factors and elements mediating this process for different mRNAs and in different animal species. We will discuss the RNA sequence elements mediating cytoplasmic polyadenylation in the 3′ untranslated regions of mRNAs, including the CPE, MBE, TCS, eCPE, and C-CPE. In addition to describing the role of general polyadenylation factors, we discuss the specific RNA binding protein families associated with cytoplasmic polyadenylation elements, including CPEB (CPEB1, CPEB2, CPEB3, and CPEB4), Pumilio (PUM2), Musashi (MSI1, MSI2), zygote arrest (ZAR2), ELAV like proteins (ELAVL1, HuR), poly(C) binding proteins (PCBP2, αCP2, hnRNP-E2), and Bicaudal C (BICC1). Some emerging themes in cytoplasmic polyadenylation will be highlighted. To facilitate understanding for those working in different organisms and fields, particularly those who are analyzing high throughput data, HUGO gene nomenclature for the human orthologs is used throughout. Where human orthologs have not been clearly identified, reference is made to protein families identified in man. © 2013 John Wiley & Sons, Ltd.

show abstract

“…The poly(rC)-binding protein αCP2 can recruit cytoplasmic poly(A) polymerase activity to mRNAs in Xenopus embryos, and this recruitment relies on C-rich sequences recognized by αCP2 (Vishnu et al 2011). This mechanism is specific for embryos and is not active in oocytes.…”

Section: 6 Xenopus Embryo-specific Translational Control Mechanismsmentioning

confidence: 99%

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

Sheets

Fox

Dowdle

et al. 2016

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

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.

show abstract

The poly(rC)-binding protein αCP2 is a noncanonical factor in X. laevis cytoplasmic polyadenylation

Cited by 13 publications

References 50 publications

Eif4a3 is required for accurate splicing of the Xenopus laevis ryanodine receptor pre-mRNA

Eif4a3 is required for accurate splicing of the Xenopus laevis ryanodine receptor pre-mRNA

Specificity factors in cytoplasmic polyadenylation

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

Contact Info

Product

Resources

About