Wnt Gene Expression During Early Embryogenesis in the Nymphalid Butterfly Bicyclus anynana

Ribonuclease protection assays have been used to quantitatively assess changes in steady-state levels of specific mRNAs during oogenesis and early embryogenesis in mice. The mRNAs encode ZP3 (a glycoprotein that serves as a sperm receptor), LDH-B (heart-type lactate dehydrogenase), and MOM-1 (a protein of unknown function). MOM-1 and LDH-B are expressed in a variety of adult mouse tissues and midgestation embryos, whereas ZP3 expression is restricted completely to oocytes. All three mRNAs are expressed by growing mouse oocytes and accumulate to unusually high levels in fully grown oocytes as compared to somatic cells; 240,000, 200,000 and 74,000 copies mRNA per fully grown oocyte for ZP3, LDH-B and MOM-1, respectively. Steady-state levels of LDH-B and MOM-1 mRNA undergo a modest decline (approximately 20–40%) during ovulation when fully grown oocytes become unfertilized eggs and, in general, mirror the reported change in poly(A)+RNA levels during this period of development. On the other hand, the level of ZP3 mRNA declines dramatically (approximately 98%) during ovulation, from approximately 240,000 copies per oocyte to approximately 5000 copies per unfertilized egg, and ZP3 mRNA is undetectable in fertilized eggs (less than 1000 copies per fertilized egg). MOM-1 mRNA is expressed at relatively low levels in morulae (approximately 2000 copies per embryo) and blastocysts (approximately 5000 copies per embryo), whereas ZP3 mRNA remains undetectable (less than 1000 copies per embryo) at these stages of preimplantation development. These findings are discussed in the context of overall gene expression during oocyte growth, meiotic maturation and early embryogenesis in mice.

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Gene expression in Xenopus embryogenesis

Development ◽

10.1242/dev.89.supplement.113 ◽

1985 ◽

Vol 89 (Supplement) ◽

pp. 113-124

Author(s):

Igor B. Dawid ◽

Susan R. Haynes ◽

Milan Jamrich ◽

Erzsebet Jonas ◽

Seiji Miyatani ◽

...

Keyword(s):

Gene Expression ◽

Protein Synthesis ◽

Xenopus Laevis ◽

Cdna Cloning ◽

Early Embryogenesis ◽

Gene Activity ◽

Complex Nature ◽

Cdna Clones ◽

Midblastula Transition ◽

First Time

This article considers some aspects of the storage of macromolecules in the oocyte of Xenopus laevis and the activation of previously unexpressed genes during early embryogenesis. The large quantity and complex nature of poly(A)+ RNA accumulated in the egg provides the cleavage embryo with a supply of mRNA sufficient to sustain protein synthesis for several hours of development. Onset of gene activity at the midblastula transition (MBT) leads to the synthesis and accumulation of molecules of various RNA classes, including tRNAs, rRNAs, mRNAs and mitochondrial RNAs. At gastrulation the poly(A)+ RNA population is still qualitatively similar to that of the egg but some sequences not present in egg RNA have accumulated by this time. Through the use of a subtractive cDNA cloning procedure we have prepared a library of sequences that represent genes activated for the first time between MBT and gastrula. A study of several of these cDNA clones suggests that genes in this class are restricted in their activity to embryonic and tadpole stages.

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The Arabidopsis RWP-RK Protein RKD4 Triggers Gene Expression and Pattern Formation in Early Embryogenesis

Current Biology ◽

10.1016/j.cub.2011.07.001 ◽

2011 ◽

Vol 21 (15) ◽

pp. 1277-1281 ◽

Cited By ~ 80

Author(s):

Takamitsu Waki ◽

Takeshi Hiki ◽

Ryouhei Watanabe ◽

Takashi Hashimoto ◽

Keiji Nakajima

Keyword(s):

Gene Expression ◽

Pattern Formation ◽

Early Embryogenesis

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PRC1-dependent compaction of Hox gene clusters prevents transcriptional derepression during early Drosophila embryogenesis

10.1101/250183 ◽

2018 ◽

Author(s):

Thierry Cheutin ◽

Giacomo Cavalli

Keyword(s):

Gene Expression ◽

Gene Clusters ◽

Higher Order ◽

Early Embryogenesis ◽

Open Chromatin ◽

Structural Constraints ◽

Chromatin Domains ◽

Hox Gene ◽

Stage Of Development ◽

Chromatin Folding

Summary paragraphPolycomb-group (PcG) proteins are conserved chromatin factors that maintain the silencing of key developmental genes, notably the Hox gene clusters, outside of their expression domains [1-3]. Polycomb repressive complex 2 (PRC2) trimethylates lysine K27 of histone H3 [4], and PRC1 collaborates with PRC2 in gene silencing. Genome-wide studies have revealed large H3K27me3 chromatin domains bound by PcG proteins, and Polycomb domains fold into distinct nuclear structures [5-9]. Although PRC1 is involved in chromatin compaction [10-16], it is unknown whether PRC1-dependent transcriptional silencing is a consequence of its role on higher-order chromatin folding. This is because depletion of PRC1 proteins typically induces both chromatin unfolding and ectopic transcription, and ectopic transcription can open chromatin by itself. To disentangle these two components, we analysed the temporal effects of two PRC1 proteins, Polyhomeotic (Ph) and Polycomb (Pc), on Hox gene clusters during Drosophila embryogenesis. We show that the absence of Ph or Pc affects the higher-order chromatin folding of Hox clusters prior to ectopic Hox gene transcription, demonstrating that PRC1 primary function during early embryogenesis is to compact its target chromatin. During later embryogenesis, we observed further chromatin opening at Hox complexes in both Ph and Pc mutants, which was coupled to strong deregulation of Hox genes at this stage of development. Moreover, the differential effects of Ph and Pc on Hox cluster folding matches the differences in ectopic Hox gene expression observed in these two mutants, suggesting that the degree of Hox derepression in PcG mutants depends on the degree of structural constraints imposed by each PcG component. In summary, our data demonstrate that binding of PRC1 to large genomic domains during early embryogenesis induces the formation of compact chromatin to prevent ectopic gene expression at later time-points. Thus, epigenetic mechanisms such as Polycomb mediated silencing act by folding chromatin domains and impose an architectural layer to gene regulation.

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194 EXPRESSION OF microRNA-15a, 16, AND 21 AND THEIR POSSIBLE ROLES IN MOUSE EMBRYOS DEVELOPING IN VITRO

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab194 ◽

2008 ◽

Vol 20 (1) ◽

pp. 176

Author(s):

D. X. Zhang ◽

X. H. Shen ◽

X. S. Cui ◽

N.-H. Kim

Keyword(s):

Gene Expression ◽

Copy Number ◽

Blastocyst Stage ◽

Early Embryogenesis ◽

Preimplantation Embryos ◽

Control Group ◽

Cell Stage ◽

Expression Levels ◽

Apoptotic Gene

MicroRNAs (miRNAs) are small (~22 nucleotides) non-coding RNA molecules that can regulate gene expression by base-pairing with fully or partially sequence-complementary target mRNAs. Hundreds of miRNAs have been identified in various multicellular organisms and many miRNAs are evolutionarily conserved. While miRNAs play an important role in animal development, little is known about their biological function during early mammalian development. In order to obtain insight into the role of miRNAs in early embryogenesis, we first determined the expression levels of three apoptosis-related miRNAs, miR-15a, -16, and -21 in mouse preimplantation embryos using TaqMan� MicroRNA Assays. Five embryos of each developmental stage were snap-frozen and amplified by stem-loop RT primer and TaqMan Universal PCR Master Mix (Applied Biosystems Inc., Foster City, CA, USA). The miRNA concentrations (10–X) in embryo samples were calculated by standard curve from synthetic lin-4 miRNA and the absolute copy number per embryo was obtained based on the formula of 6.02 � 10(8–X). All three miRNAs had low expression levels from the zygote to the 8-cell stage and were up-regulated thereafter. In general, among the three miRNAs, miR-15a exhibited the lowest expression in preimplantation embryos, while miR-16 exhibited the highest. Because of the low levels of miRNA-15a, we determined developmental ability and apoptosis of embryos following microinjection of miRNA-15a. The microinjection of miR-15a into zygotes did not affect embryo development up to the blastocyst stage (miR-15a, 90 � 4.5% v. buffer 94.6 � 5.8%); however, it did induce a significant degree of apoptosis (P < 0.05; Tukey's multiple range test). Furthermore, the expression levels of miR-15a and -16 were increased in microinjected blastocysts compared to the control group (copy number per blastocyst, miR-15a, 6991 � 1223 v. 3098 � 592; miR-16, 196216 � 958 v. 133514 � 6059). Real-time RT-PCR data showed that the gene expression levels of the housekeeping gene GAPDH, the anti-apoptotic gene Bcl-xL, and the miRNA pathway-related genes GW182 and Dicer remained unchanged in miR-15a-injected blastocysts compared to the control group. In contrast, the expression of the stem cell-specific transcriptional factor Oct-4 (fold change, 1.451 � 0.12), the pro-apoptotic gene Bax (1.418 � 0.12), and Caspase 3 (1.314 � 0.19) were significantly increased in microinjected blastocysts. In addition, treatment of 2-cell embryos with 600 µm H2O2 induced apoptosis and increased the expression level of miR-16 at the blastocyst stage (P < 0.05). Taken together, the changes in the expression levels of miR-15a, -16, and -21 in various embryonic developmental stages indicate a possible role for them in early embryogenesis. Furthermore, the high expression levels of miR-15a and miR-16 seem to be linked to apoptosis in blastocyst-stage embryos; this may be due to an increase in the expression of pro-apoptotic genes.

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A Single Origin for Nymphalid Butterfly Eyespots Followed by Widespread Loss of Associated Gene Expression

PLoS Genetics ◽

10.1371/journal.pgen.1002893 ◽

2012 ◽

Vol 8 (8) ◽

pp. e1002893 ◽

Cited By ~ 63

Author(s):

Jeffrey C. Oliver ◽

Xiao-Ling Tong ◽

Lawrence F. Gall ◽

William H. Piel ◽

Antónia Monteiro

Keyword(s):

Gene Expression ◽

Single Origin ◽

Nymphalid Butterfly

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EphB2/B3 gene expression is down-regulated during early embryogenesis in the cadmium-induced omphalocele chick model

Journal of Pediatric Surgery ◽

10.1016/j.jpedsurg.2012.01.045 ◽

2012 ◽

Vol 47 (5) ◽

pp. 920-924 ◽

Cited By ~ 6

Author(s):

Takashi Doi ◽

Prem Puri ◽

John Bannigan ◽

Jennifer Thompson

Keyword(s):

Gene Expression ◽

Early Embryogenesis

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Molecular mechanisms underlying simplification of venation patterns in holometabolous insects

Development ◽

10.1242/dev.196394 ◽

2020 ◽

Vol 147 (23) ◽

pp. dev196394

Author(s):

Tirtha Das Banerjee ◽

Antónia Monteiro

Keyword(s):

Gene Expression ◽

Pattern Formation ◽

Molecular Mechanisms ◽

Positional Information ◽

Butterfly Species ◽

Central Research ◽

Bicyclus Anynana ◽

Wing Vein ◽

Text Book ◽

Research Theme

ABSTRACTHow mechanisms of pattern formation evolve has remained a central research theme in the field of evolutionary and developmental biology. The mechanism of wing vein differentiation in Drosophila is a classic text-book example of pattern formation using a system of positional information, yet very little is known about how species with a different number of veins pattern their wings, and how insect venation patterns evolved. Here, we examine the expression pattern of genes previously implicated in vein differentiation in Drosophila in two butterfly species with more complex venation Bicyclus anynana and Pieris canidia. We also test the function of some of these genes in B. anynana. We identify both conserved as well as new domains of decapentaplegic, engrailed, invected, spalt, optix, wingless, armadillo, blistered and rhomboid gene expression in butterflies, and propose how the simplified venation in Drosophila might have evolved via loss of decapentaplegic, spalt and optix gene expression domains, via silencing of vein-inducing programs at Spalt-expression boundaries, and via changes in expression of vein maintenance genes.

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