Three Strongylocentrotus purpuratus actin genes show correct cell-specific expression in hybrid embryos of S. purpuratus and Lytechinus pictus

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 407-413 ◽  
Author(s):  
P.E. Nisson ◽  
L.E. Dike ◽  
W.R. Crain

The cell-specific expression of three actin genes from the sea urchin species Strongylocentrotus purpuratus was examined in hybrid embryos of S. purpuratus and another species, Lytechinus pictus, by in situ hybridization. The mRNAs from each of these genes displayed distinct spatial patterns of expression in late-stage hybrid embryos (constructed in either direction), being detected only in the cell lineages where they are normally found in S. purpuratus embryos (i.e. CyIIIa, only in the aboral ectoderm lineage; CyI, in the gut, oral ectoderm and some mesenchyme cells of plutei, and preferentially in the archenteron of gastrulae; M, only in two small clusters of cells near the esophagus in plutei). These results, together with our previous observation that expression of each of these genes is activated at the same stage in these hybrid embryos as in normal S. purpuratus embryos, demonstrate that the trans-acting factors which are necessary to regulate both the temporal and spatial expression of these genes are present in the hybrid embryos. Previous experiments have shown that the expression of a chimeric gene containing the CyIIIa promoter fused to a bacterial chloramphenicol actetyltransferase (CAT) gene is not confined to the correct cell lineage (aboral ectoderm) when injected into Lytechinus embryos. The conclusion from these sets of data is that the factor(s) that regulate the spatial expression of at least one of the actin genes must derive from transcription of the zygotic genome.

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
A.H. Wikramanayake ◽  
B.P. Brandhorst ◽  
W.H. Klein

During early embryogenesis, the highly regulative sea urchin embryo relies extensively on cell-cell interactions for cellular specification. Here, the role of cellular interactions in the temporal and spatial expression of markers for oral and aboral ectoderm in Strongylocentrotus purpuratus and Lytechinus pictus was investigated. When pairs of mesomeres or animal caps, which are fated to give rise to ectoderm, were isolated and cultured they developed into ciliated embryoids that were morphologically polarized. In animal explants from S. purpuratus, the aboral ectoderm-specific Spec1 gene was activated at the same time as in control embryos and at relatively high levels. The Spec1 protein was restricted to the squamous epithelial cells in the embryoids suggesting that an oral-aboral axis formed and aboral ectoderm differentiation occurred correctly. However, the Ecto V protein, a marker for oral ectoderm differentiation, was detected throughout the embryoid and no stomodeum or ciliary band formed. These results indicated that animal explants from S. purpuratus were autonomous in their ability to form an oral-aboral axis and to differentiate aboral ectoderm, but other aspects of ectoderm differentiation require interaction with vegetal blastomeres. In contrast to S. purpuratus, aboral ectoderm-specific genes were not expressed in animal explants from L. pictus even though the resulting embryoids were morphologically very similar to those of S. purpuratus. Recombination of the explants with vegetal blastomeres or exposure to the vegetalizing agent LiCl restored activity of aboral ectoderm-specific genes, suggesting the requirement of a vegetal induction for differentiation of aboral ectoderm cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 41-50 ◽  
Author(s):  
B.R. Hough-Evans ◽  
R.R. Franks ◽  
R.W. Zeller ◽  
R.J. Britten ◽  
E.H. Davidson

The CyIIIa.CAT fusion gene was injected into Strongylocentrotus purpuratus eggs, together with excess ligated competitor sequences representing subregions of the CyIIIa regulatory domain. In this construct, the chloramphenicol acetyltransferase (CAT) reporter gene is placed under the control of the 2300 nucleotide upstream regulatory domain of the lineage-specific CyIIIa cytoskeletal actin gene. CAT mRNA was detected by in situ hybridization in serial sections of pluteus stage embryos derived from the injected eggs. When carrier DNA lacking competitor CyIIIa fragments was coinjected with CyIIIa.CAT, CAT mRNA was observed exclusively in aboral ectoderm cells, i.e. the territory in which the CyIIIa gene itself is normally expressed (as also reported by us previously). The same result was obtained when five of seven different competitor subfragments bearing sites of DNA-protein interaction were coinjected. However, coinjection of excess quantities of either of two widely separated, nonhomologous fragments of the CyIIIa regulatory domain produced a dramatic ectopic expression of CAT mRNA in the recipient embryos. CAT mRNA was observed in gut, mesenchyme cells and oral ectoderm in these embryos. We conclude that these fragments contain regulatory sites that negatively control spatial expression of the CyIIIa gene.


Development ◽  
1992 ◽  
Vol 114 (1) ◽  
pp. 193-201 ◽  
Author(s):  
P.E. Nisson ◽  
M.F. Gaudette ◽  
B.P. Brandhorst ◽  
W.R. Crain

The expression of the Spec1 gene of Strongylocentrotus purpuratus and its Lytechinus pictus homologue LpS1 was analyzed in reciprocal hybrid embryos of these two species of sea urchin. While the time course of accumulation of Spec1 mRNA was nearly normal in hybrid embryo populations, the accumulation of LpS1 mRNA was not. This was particularly evident in plutei, where the level of LpS1 mRNA was less than 5% that in normal L. pictus plutei. In situ hybridization analysis of serial sections indicated that LpS1 mRNA was detectable in only about 2% of hybrid plutei in either cross, whereas Spec1 mRNA was present in nearly all hybrid plutei; expression of either homologue was appropriately restricted to the aboral ectoderm. In crosses of L. pictus eggs with S. purpuratus sperm (LpSp), about 1% of hybrid plutei expressed LpS1 RNA in most or all aboral ectoderm cells at normal levels, and did not express Spec1 RNA; in another 1% of the LpSp hybrid plutei the Spec1 and LpS1 transcripts were present at normal levels in complementary, non-overlapping patches of contiguous aboral ectoderm cells. In the reciprocal SpLp cross, each hybrid pluteus expressed either only the LpS1 gene (about 2%) or only the Spec1 gene throughout the aboral ectoderm. In SpLp hybrid gastrulae the level of LpS1 mRNA was less restricted; about 2% of the embryos contained only LpS1 RNA, and about half expressed only Spec1 transcripts, but in the remaining embryos Spec1 and LpS1 transcripts were coexpressed in the same aboral ectoderm cells.(ABSTRACT TRUNCATED AT 250 WORDS)


2016 ◽  
Author(s):  
Sabrina M. Schiemann ◽  
José M. Martín-Durán ◽  
Aina Børve ◽  
Bruno C. Vellutini ◽  
Yale J. Passamaneck ◽  
...  

AbstractTemporal collinearity is often regarded as the force preserving Hox clusters in vertebrate genomes. Studies that combine genomic and gene expression data in invertebrates would allow generalizing this observation across all animals, but are scarce, particularly within Lophotrochozoa (e.g., snails and segmented worms). Here, we use two brachiopod species –Terebratalia transversa, Novocrania anomala– to characterize the complement, cluster and expression of their Hox genes. T. transversa has an ordered, split cluster with ten genes (lab, pb, Hox3, dfd, scr, lox5, antp, lox4, post2, post1), while N. anomala has nine (missing post1). Our in situ hybridization, qPCR and stage specific transcriptomic analyses show that brachiopod Hox genes are neither strictly temporally nor spatially collinear; only pb (in T. transversa), Hox3 and dfd (in both brachiopods) show staggered mesodermal expression. The spatial expression of the Hox genes in both brachiopod species correlates with their morphology and demonstrates cooption of Hox genes in the chaetae and shell fields, two major lophotrochozoan morphological novelties. The shared and specific expression of a subset of Hox genes, Arx and Zic orthologs in chaetae and shell-fields between brachiopods, mollusks, and annelids supports the deep conservation of the molecular basis forming these lophotrochozoan hallmarks. Our findings challenge that collinearity alone preserves lophotrochozoan Hox clusters, indicating that additional genomic traits need to be considered in understanding Hox evolution.


1986 ◽  
Vol 6 (7) ◽  
pp. 2602-2612
Author(s):  
T Lieber ◽  
K Weisser ◽  
G Childs

We analyzed the histone mRNA population found in several adult tissues of the sea urchin Strongylocentrotus purpuratus and in testis of Lytechinus pictus. Unique species of H1 and H2b mRNAs encoding the sperm-specific histone subtypes can be found exclusively in testis RNA. S. purpuratus contains two distinct testis-specific H1 transcripts, while L. pictus contains one such transcript. Each of these mRNAs is larger than either early or late embryonic H1 mRNAs. Other somatic adult tissues contain transcripts derived from members of the late embryonic H1 histone gene family. S. purpuratus contains one H2b transcript found exclusively in testis, while L. pictus contains two such H2b mRNAs. Similarly, in tissues other than testis, late H2b transcripts were found. While there is no sperm-specific H2a protein, a limited set of late histone H2a genes encoding primarily the H2a-beta subtype is expressed in testis. The majority of the H2a protein found in diploid adult tissues is also the H2a-beta subtype; however, the size of the H2a transcripts differs between testis and other tissues. We conclude that different members of the late H2a gene family are differentially expressed in embryos and adult tissues. We prepared and characterized cDNA clones encoding the sperm-specific H2b protein as well as the H2a-beta protein found in testis.


1986 ◽  
Vol 6 (7) ◽  
pp. 2602-2612 ◽  
Author(s):  
T Lieber ◽  
K Weisser ◽  
G Childs

We analyzed the histone mRNA population found in several adult tissues of the sea urchin Strongylocentrotus purpuratus and in testis of Lytechinus pictus. Unique species of H1 and H2b mRNAs encoding the sperm-specific histone subtypes can be found exclusively in testis RNA. S. purpuratus contains two distinct testis-specific H1 transcripts, while L. pictus contains one such transcript. Each of these mRNAs is larger than either early or late embryonic H1 mRNAs. Other somatic adult tissues contain transcripts derived from members of the late embryonic H1 histone gene family. S. purpuratus contains one H2b transcript found exclusively in testis, while L. pictus contains two such H2b mRNAs. Similarly, in tissues other than testis, late H2b transcripts were found. While there is no sperm-specific H2a protein, a limited set of late histone H2a genes encoding primarily the H2a-beta subtype is expressed in testis. The majority of the H2a protein found in diploid adult tissues is also the H2a-beta subtype; however, the size of the H2a transcripts differs between testis and other tissues. We conclude that different members of the late H2a gene family are differentially expressed in embryos and adult tissues. We prepared and characterized cDNA clones encoding the sperm-specific H2b protein as well as the H2a-beta protein found in testis.


2010 ◽  
Vol 4 (1) ◽  
pp. 223-229 ◽  
Author(s):  
Andrew Cho ◽  
Shigeki Suzuki ◽  
Junko Hatakeyama ◽  
Naoto Haruyama ◽  
Ashok B Kulkarni

Tooth and bone specimen require extensive demineralization for careful analysis of cell morphology, as well as gene and protein expression levels. The LacZ gene, which encodes the ß-galactosidase enzyme, is often used as a reporter gene to study gene-structure function, tissue-specific expression by a promoter, cell lineage and fate. This reporter gene is particularly useful for analyzing the spatial and temporal gene expression pattern, by expressing the LacZ gene under the control of a promoter of interest. To analyze LacZ activity, and the expression of other genes and their protein products in teeth and bones, it is necessary to carry out a complete demineralization of the specimen before cutting sections. However, strong acids, such as formic acid used for tooth demineralization, destroy the activities of enzymes including those of ß-galactosidase. Therefore, most protocols currently use mild acids such as 0.1 M ethylene diamine tetra-acetic acid (EDTA) for demineralization of tooth and bone specimen, which require a longer period of treatment for complete demineralization. A method by which hard tissue specimens such as teeth and bones can be rapidly, but gently, decalcified is necessary to save time and effort. Here, we report a suitable method for rapid demineralization of mouse teeth in 0.1M EDTA at 42˚C without any loss of ß-galactosidase activity.


2007 ◽  
Vol 7 ◽  
pp. 1470-1492 ◽  
Author(s):  
Aartjan J. W. te Velthuis ◽  
Christoph P. Bagowski

PDZ/LIM genes encode a group of proteins that play very important, but diverse, biological roles. They have been implicated in numerous vital processes, e.g., cytoskeleton organization, neuronal signaling, cell lineage specification, organ development, and oncogenesis.In mammals, there are ten genes that encode for both a PDZ domain, and one or several LIM domains: four genes of the ALP subfamily (ALP, Elfin, Mystique, and RIL), three of the Enigma subfamily (Enigma, Enigma Homolog, and ZASP), the two LIM kinases (LIMK1 and LIMK2), and the LIM only protein 7 (LMO7). Functionally, all PDZ and LIM domain proteins share an important trait, i.e., they can associate with and/or influence the actin cytoskeleton.We review here the PDZ and LIM domain—encoding genes and their different gene structures, their binding partners, and their role in development and disease. Emphasis is laid on the important questions: why the combination of a PDZ domain with one or more LIM domains is found in such a diverse group of proteins, and what role the PDZ/LIM module could have in signaling complex assembly and localization.Furthermore, the current knowledge on splice form specific expression and the function of these alternative transcripts during vertebrate development will be discussed, since another source of complexity for the PDZ and LIM domain—encoding proteins is introduced by alternative splicing, which often creates different domain combinations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jillian L. Lindblad ◽  
Meghana Tare ◽  
Alla Amcheslavsky ◽  
Alicia Shields ◽  
Andreas Bergmann

AbstractThe initiator caspase Dronc is the only CARD-domain containing caspase in Drosophila and is essential for apoptosis. Here, we report that homozygous dronc mutant adult animals are short-lived due to the presence of a poorly developed, defective and leaky intestine. Interestingly, this mutant phenotype can be significantly rescued by enteroblast-specific expression of dronc+ in dronc mutant animals, suggesting that proper Dronc function specifically in enteroblasts, one of four cell types in the intestine, is critical for normal development of the intestine. Furthermore, enteroblast-specific knockdown of dronc in adult intestines triggers hyperplasia and differentiation defects. These enteroblast-specific functions of Dronc do not require the apoptotic pathway and thus occur in a non-apoptotic manner. In summary, we demonstrate that an apoptotic initiator caspase has a very critical non-apoptotic function for normal development and for the control of the cell lineage in the adult midgut and therefore for proper physiology and homeostasis.


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