Progressively restricted expression of a new homeobox-containing gene during Xenopus laevis embryogenesis

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1179-1187 ◽  
Author(s):  
M.W. Su ◽  
H.R. Suzuki ◽  
M. Solursh ◽  
F. Ramirez
Keyword(s):  
Mrna Levels ◽  
Gastrula Stage ◽  
Lateral Plate ◽  
Dorsal Neural Tube ◽  
Tailbud Stage ◽  
The Central Nervous System ◽  
Development Levels ◽  
Dorsal Hindbrain ◽  
Early Gastrula

We have isolated cDNAs encoding a novel Xenopus homeodomain-containing protein homologous to the mouse Hox-7.1 and the Drosophila muscle segment homebox (msh). Northern blot and RNAase protection experiments established that transcripts of the frog gene, termed Xhox-7.1, first appear at about the beginning of gastrulation. After a rapid increase, mRNA levels plateau between the neurula and middle-tailbud stages, and decrease steadily thereafter. In situ hybridization localized the Xhox-7.1 message to the dorsal mesodermal mantle of gastrula stage embryos. Comparison of the hybridization patterns of progressively more anterior cross-section of tailbud stage embryos localized the signal to the dorsal neural tube and neural crest, to specific regions of the lateral plate mesoderm, and to the cardiogenic region. By the tadpole stage, the Xhox-7.1 message appears only at specific sites in the central nervous system, such as in the dorsal hindbrain. Thus, during embryonic development levels of Xhox-7.1 expression decrease as the transcript becomes more progressively localized. Finally, evidence is presented of a distinct msh-like transcript (provisionally termed Xhox-7.1′) which begins to accumulate at early-gastrula stage, as well.

Zic3 is involved in the left-right specification of the Xenopus embryo

Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4787-4795 ◽  
Author(s):  
T. Kitaguchi ◽  
T. Nagai ◽  
K. Nakata ◽  
J. Aruga ◽  
K. Mikoshiba
Keyword(s):  
Molecular Basis ◽  
Xenopus Embryo ◽  
Zinc Finger Domain ◽  
Lateral Plate Mesoderm ◽  
Vertebrate Development ◽  
Gastrula Stage ◽  
Lateral Plate ◽  
The Right ◽  
Early Gastrula ◽  
Pitx2 Expression

Establishment of left-right (L-R) asymmetry is fundamental to vertebrate development. Several genes involved in L-R asymmetry have been described. In the Xenopus embryo, Vg1/activin signals are implicated upstream of asymmetric nodal related 1 (Xnr1) and Pitx2 expression in L-R patterning. We report here that Zic3 carries the left-sided signal from the initial activin-like signal to determinative factors such as Pitx2. Overexpression of Zic3 on the right side of the embryo altered the orientation of heart and gut looping, concomitant with disturbed laterality of expression of Xnr1 and Pitx2, both of which are normally expressed in the left lateral plate mesoderm. The results indicate that Zic3 participates in the left-sided signaling upstream of Xnr1 and Pitx2. At early gastrula, Zic3 was expressed not only in presumptive neuroectoderm but also in mesoderm. Correspondingly, overexpression of Zic3 was effective in the L-R specification at the early gastrula stage, as revealed by a hormone-inducible Zic3 construct. The Zic3 expression in the mesoderm is induced by activin (beta) or Vg1, which are also involved in the left-sided signal in L-R specification. These findings suggest that an activin-like signal is a potent upstream activator of Zic3 that establishes the L-R axis. Furthermore, overexpression of the zinc-finger domain of Zic3 on the right side is sufficient to disturb the L-R axis, while overexpression of the N-terminal domain on the left side affects the laterality. These results suggest that Zic3 has at least two functionally important domains that play different roles and provide a molecular basis for human heterotaxy, which is an L-R pattern anomaly caused by a mutation in human ZIC3.

scholarly journals Role of the lncRNA BACE1-AS in shared disease mechanisms between heart failure and Alzheimer's disease

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Greco ◽  
A Made' ◽  
A.S Tascini ◽  
J Garcia Manteiga ◽  
S Castelvecchio ◽  
...  
Keyword(s):  
Heart Failure ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
In Situ Hybridization ◽  
Cell Apoptosis ◽  
Common Disease ◽  
Funding Source ◽  
Mrna Levels ◽  
Rna Seq

Abstract Background BACE1 encodes for β-secretase, the key enzyme involved in β-amyloid (βA) generation, a peptide well known for its involvement in Alzheimer's disease (AD). Of note, heart failure (HF) and AD share several risk factors and effectors. We recently showed that, in the heart of ischemic HF patients, the levels of both BACE1, its antisense RNA BACE1-AS and βA are all increased. BACE1-AS positively regulates the expression of BACE1, triggering βA intracellular accumulation, and its overexpression or βA administration induce cardiovascular-cell apoptosis. Aim To characterize the transcripts of the BACE1 locus and to investigate the molecular mechanisms underpinning BACE1-AS regulation of cell vitality. Methods By PCR and sequencing, we studied in the heart the expression of a variety of antisense BACE1 transcripts predicted by FANTOM CAT Epigenome. We studied BACE1 RNA stability by BrdU pulse chase experiments (BRIC assay). The cellular localization of BACE1-AS RNA was investigated by in situ hybridization assay. BACE1-AS binding RNAs were evaluated by BACE1-AS-MS2-Tag pull-down in AC16 cardiomyocytes followed by RNA-seq. Enriched RNAs were validated by qPCR and analysed by bioinformatics comparison with publicly available gene expression datasets of AD brains. Results We readily detected several antisense BACE1 transcripts expressed in AC16 cardiomyocytes; however, only BACE1-AS RNAs overlapping exon 6 of BACE1 positively regulated BACE1 mRNA levels, acting by increasing its stability. BACE1 silencing reverted cell apoptosis induced by BACE1-AS expression, indicating that BACE1 is a functional target of BACE1-AS. However, in situ hybridization experiments indicated a mainly nuclear localization for BACE1-AS, which displayed a punctuated distribution, compatible with chromatin association and indicative of potential additional targets. To identify other BACE1-AS binding RNAs, a BACE1-AS-MS2-tag pull-down was performed and RNA-seq of the enriched RNAs identified 698 BACE1-AS interacting RNAs in cardiomyocytes. Gene ontology of the BACE1-AS binding RNAs identified categories of relevance for cardiovascular or neurological diseases, such as dopaminergic synapse, glutamatergic synapse, calcium signalling pathway and voltage-gated channel activity. In spite of the differences between brain and heart transcriptomes, BACE1-AS-interacting RNAs identified in cardiomyocytes were significantly enriched in transcripts differentially expressed in AD brains as well as in RNAs expressed by enhancer genomic regions that are significantly hypomethylated in AD brains. Conclusions These data shed a new light on the complexity of BACE1-AS locus and on the existence of RNAs interacting with BACE1-AS with a potential as enhancer-RNAs. Moreover, the dysregulation of the BACE1-AS/BACE1/βA pathway may be a common disease mechanism shared by cardiovascular and neurological degenerative diseases. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Italian Health Ministery_Ricerca Corrente 2020

Expression of a novel FGF in the Xenopus embryo. A new candidate inducing factor for mesoderm formation and anteroposterior specification

Development ◽  
1992 ◽  
Vol 114 (3) ◽  
pp. 711-720 ◽  
Author(s):  
H.V. Isaacs ◽  
D. Tannahill ◽  
J.M. Slack
Keyword(s):  
Specific Activity ◽  
Biological Properties ◽  
The Body ◽  
Mesoderm Induction ◽  
Gastrula Stage ◽  
Blastula Stage ◽  
Mesoderm Formation ◽  
Low Levels

We have cloned and sequenced a new member of the fibroblast growth factor family from Xenopus laevis embryo cDNA. It is most closely related to both mammalian kFGF (FGF-4) and FGF-6 but as it is not clear whether it is a true homologue of either of these genes we provisionally refer to it as XeFGF (Xenopus embryonic FGF). Two sequences were obtained, differing by 11% in derived amino acid sequence, which probably represent pseudotetraploid variants. Both the sequence and the behaviour of in vitro translated protein indicates that, unlike bFGF (FGF-2), XeFGF is a secreted molecule. Recombinant XeFGF protein has mesoderm-inducing activity with a specific activity similar to bFGF. XeFGF mRNA is expressed maternally and zygotically with a peak during the gastrula stage. Both probe protection and in situ hybridization showed that the zygotic expression is concentrated in the posterior of the body axis and later in the tailbud. Later domains of expression were found near the midbrain/hindbrain boundary and at low levels in the myotomes. Because of its biological properties and expression pattern, XeFGF is a good candidate for an inducing factor with possible roles both in mesoderm induction at the blastula stage and in the formation of the anteroposterior axis at the gastrula stage.

Muscle gene activation in Xenopus requires intercellular communication during gastrula as well as blastula stages

Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 137-142 ◽  
Author(s):  
J. B. Gurdon ◽  
K. Kao ◽  
K. Kato ◽  
N. D. Hopwood
Keyword(s):  
Protein Synthesis ◽  
Developmental Stage ◽  
Cell Transplantation ◽  
Intercellular Communication ◽  
Gene Activation ◽  
Gastrula Stage ◽  
Blastula Stage ◽  
Morphological Marker ◽  
Muscle Gene ◽  
Early Gastrula

In Xenopus an early morphological marker of mesodermal induction is the elongation of the mesoderm at the early gastrula stage (Symes and Smith, 1987). We show here that the elongation of equatorial (marginal) tissue is dependent on protein synthesis in a mid blastula, but has become independent of it by the late blastula stage. In animal caps induced to become mesoderm, the time when protein synthesis is required for subsequent elongation immediately follows the time of induction, and is not related to developmental stage. For elongation, intercellular communication during the blastula stage is of primary importance. Current experiments involving cell transplantation indicate a need for further celhcell interactions during gastrulation, and therefore after the vegetal-animal induction during blastula stages. These secondary cell interactions are believed to take place among cells that have already received a vegetal induction, and may facilitate some of the later intracellular events known to accompany muscle gene activation.

Expression of N-CAM precedes neural induction in Pleurodeles waltl (urodele, amphibian)

Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 675-683 ◽  
Author(s):  
J.P. Saint-Jeannet ◽  
F. Foulquier ◽  
C. Goridis ◽  
A.M. Duprat
Keyword(s):  
Monoclonal Antibody ◽  
Nervous System ◽  
Xenopus Laevis ◽  
Neural Induction ◽  
Gastrula Stage ◽  
Pleurodeles Waltl ◽  
Early Gastrula

The appearance and localization of N-CAM during neural induction were studied in Pleurodeles waltl embryos and compared with recent contradictory results reported in Xenopus laevis. A monoclonal antibody raised against mouse N-CAM was used. In the nervous system of Pleurodeles, it recognized two glycoproteins of 180 and 140×10(3) M(r) which are the Pleurodeles equivalent of N-CAM-180 and -140. Using this probe for immunohistochemistry and immunocytochemistry, we showed that N-CAM was already expressed in presumptive ectoderm at the early gastrula stage. In late gastrula embryos, a slight increase in staining was observed in the neurectoderm, whereas the labelling persisted in the noninduced ectoderm. When induced ectodermal cells were isolated at the late gastrula stage and cultured in vitro up to 14 days, a faint polarized labelling of cells was observed initially. During differentiation, the staining increased and became progressively restricted to differentiating neurons.

Mouse Wnt genes exhibit discrete domains of expression in the early embryonic CNS and limb buds

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 247-261 ◽  
Author(s):  
B.A. Parr ◽  
M.J. Shea ◽  
G. Vassileva ◽  
A.P. McMahon
Keyword(s):  
Limb Development ◽  
Expression Patterns ◽  
Limb Buds ◽  
Expression Studies ◽  
The Family ◽  
The Central Nervous System ◽  
Discrete Domains ◽  
Early Developmental ◽  
The Brain

Mutation and expression studies have implicated the Wnt gene family in early developmental decision making in vertebrates and flies. In a detailed comparative analysis, we have used in situ hybridization of 8.0- to 9.5-day mouse embryos to characterize expression of all ten published Wnt genes in the central nervous system (CNS) and limb buds. Seven of the family members show restricted expression patterns in the brain. At least three genes (Wnt-3, Wnt-3a, and Wnt-7b) exhibit sharp boundaries of expression in the forebrain that may predict subdivisions of the region later in development. In the spinal cord, Wnt-1, Wnt-3, and Wnt-3a are expressed dorsally, Wnt-5a, Wnt-7a, and Wnt-7b more ventrally, and Wnt-4 both dorsally and in the floor plate. In the forelimb primordia, Wnt-3, Wnt-4, Wnt-6 and Wnt-7b are expressed fairly uniformly throughout the limb ectoderm. Wnt-5a RNA is distributed in a proximal to distal gradient through the limb mesenchyme and ectoderm. Along the limb's dorsal-ventral axis, Wnt-5a is expressed in the ventral ectoderm and Wnt-7a in the dorsal ectoderm. We discuss the significance of these patterns of restricted and partially overlapping domains of expression with respect to the putative function of Wnt signalling in early CNS and limb development.

Contrasting patterns of c-myc and N-myc expression in proliferating, quiescent, and differentiating cells of the embryonic chicken lens

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 813-820
Author(s):  
L.L. Harris ◽  
J.C. Talian ◽  
P.S. Zelenka
Keyword(s):  
Cell Proliferation ◽  
Protein Product ◽  
Mrna Levels ◽  
Lens Fiber ◽  
Proliferating Cells ◽  
Fiber Cells ◽  
Embryonic Chicken ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation

The present study uses the polymerase chain reaction and in situ hybridization to examine c-myc and N-myc mRNA in the embryonic chicken lens at 6, 10, 14 and 19 days of development and compares the pattern of expression obtained with the developmental pattern of cell proliferation and differentiation. In the central epithelium, c-myc mRNA levels were proportional to the percentage of proliferating cells throughout development. N-myc mRNA expression in this region was relatively low and showed no correlation with cell proliferation. The ratio of N-myc to c-myc mRNA increased markedly with the onset of epithelial cell elongation and terminal fiber cell differentiation, although both c-myc and N-myc mRNAs continued to be expressed in postmitotic, elongating cells of the equatorial epithelium and in terminally differentiating lens fiber cells. Thus, increased expression of N-myc, a gene whose protein product may compete with c-myc protein for dimerization partners, accompanies the dissociation of c-myc expression and cell proliferation during terminal differentiation of lens fiber cells.

Mouse Hox-3.4: homeobox sequence and embryonic expression patterns compared with other members of the Hox gene network

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 329-339 ◽  
Author(s):  
S.J. Gaunt ◽  
P.L. Coletta ◽  
D. Pravtcheva ◽  
P.T. Sharpe
Keyword(s):  
Gene Network ◽  
Common Ancestor ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Predicted Amino Acid Sequence ◽  
Chromosome 15 ◽  
Hox Gene ◽  
The Central Nervous System ◽  
Genomic Organisation

A putative mouse homeobox gene (Hox-3.4) was previously identified 4kb downstream of the Hox-3.3 (Hox-6.1)* gene (Sharpe et al. 1988). We have now sequenced the Hox-3.4 homeobox region. The predicted amino acid sequence shows highest degree of homology in the mouse with Hox-1.3 and -2.1. This, together with similarities in the genomic organisation around these three genes, suggests that they are comembers of a subfamily, derived from a common ancestor. Hox-3.4 appears to be a homologue of the Xenopus Xlhbox5 and human cp11 genes (Fritz and De Robertis, 1988; Simeone et al. 1988). Using a panel of mouse-hamster somatic cell hybrids we have mapped the Hox-3.4 gene to chromosome 15. From the results of in situ hybridization experiments, we describe the distribution of Hox-3.4 transcripts within the 12 1/2 day mouse embryo, and we compare this with the distributions of transcripts shown by seven other members of the Hox gene network. We note three consistencies that underlie the patterns of expression shown by Hox-3.4. First, the anterior limits of Hox-3.4 transcripts in the embryo are related to the position of the Hox-3.4 gene within the Hox-3 locus. Second, the anterior limits of Hox-3.4 expression within the central nervous system are similar to those shown by subfamily homologues Hox-2.1 and Hox-1.3, although the tissue-specific patterns of expression for these three genes show many differences. Third, the patterns of Hox-3.4 expression within the spinal cord and the testis are very similar to those shown by a neighbouring Hox-3 gene (Hox-3.3), but they are quite different from those shown by Hox-1 genes (Hox-1.2, -1.3 and -1.4).

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