A POU gene required for early cleavage and protein accumulation in the sea urchin embryo

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1929-1935 ◽  
Author(s):  
B.R. Char ◽  
H. Tan ◽  
R. Maxson
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Antisense Oligodeoxynucleotides ◽  
Protein Accumulation ◽  
Antisense Inhibition ◽  
Early Cleavage ◽  
Sea Urchin Embryo ◽  
Classical Work ◽  
Zygotic Transcription ◽  
New Protein

SpOct is a POU gene expressed during oogenesis and early embryogenesis of the sea urchin, Strongylocentrotus purpuratus. In the first use of antisense technology in the sea urchin embryo, we report that disruption of SpOct gene function in 1-cell zygotes by the injection of antisense oligodeoxynucleotides arrests development prior to the first cell division. We show that single-stranded antisense oligodeoxynucleotides specifically block cleavage, and that injection of SpOct mRNA overcomes this block. The accumulation of [35S]methionine into zygotically synthesized protein is significantly reduced in antisense-injected embryos. DNA synthesis is also reduced by the antisense regimen as expected from the antisense inhibition of protein accumulation. That protein accumulation prior to the first cleavage is retarded by antisense targeting of a transcription factor is very surprising in light of classical work showing that the activation of protein synthesis does not require zygotic transcription. We conclude that either some new transcription is obligate for the accumulation of new protein, or that the SpOct gene plays a novel, non-transcriptional role in this process.

Autonomous and non-autonomous differentiation of ectoderm in different sea urchin species

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
A.H. Wikramanayake ◽  
B.P. Brandhorst ◽  
W.H. Klein
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Protein A ◽  
Cellular Interactions ◽  
V Protein ◽  
Lytechinus Pictus ◽  
Sea Urchin Embryo ◽  
Oral Ectoderm ◽  
Temporal And Spatial

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)

scholarly journals The oral-aboral axis of a sea urchin embryo is specified by first cleavage

Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 641-647 ◽  
Author(s):  
R.A. Cameron ◽  
S.E. Fraser ◽  
R.J. Britten ◽  
E.H. Davidson
Keyword(s):  
Sea Urchin ◽  
Cleavage Plane ◽  
Strongylocentrotus Purpuratus ◽  
Cell Stage ◽  
Animal Pole ◽  
Sea Urchin Embryo ◽  
The Future ◽  
Axis Specification ◽  
The Right ◽  
Lines Of Evidence

Several lines of evidence suggest that the oral-aboral axis in Strongylocentrotus purpuratus embryos is specified at or before the 8-cell stage. Were the oral-aboral axis specified independently of the first cleavage plane, then a random association of this plane with the blastomeres of the four embryo quadrants in the oral-aboral plane (viz. oral, aboral, right and left) would be expected. Lineage tracer dye injection into one blastomere at the 2-cell stage and observation of the resultant labeling patterns demonstrates instead a strongly nonrandom association. In at least ninety percent of cases, the progeny of the aboral blastomeres are associated with those of the left lateral blastomeres and the progeny of the oral blastomeres with the right lateral ones, respectively. Thus, ninety percent of the time the oral pole of the future oral-aboral axis lies 45 degrees clockwise from the first cleavage plane as viewed from the animal pole. The nonrandom association of blastomeres after labeling of the 2-cell stage implies that there is a mechanistic relation between axis specification and the positioning of the first cleavage plane.

Combinatorial regulation by promoter and intron 1 regions of the metallothionein SpMTA gene in the sea urchin embryo

1993 ◽  
Vol 13 (2) ◽  
pp. 993-1001
Author(s):  
G Bai ◽  
E W Stuebing ◽  
H R Parker ◽  
P Harlow ◽  
M Nemer
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Middle Region ◽  
Interior Region ◽  
Induced Expression ◽  
Combinatorial Regulation ◽  
Response Elements ◽  
Sea Urchin Embryo ◽  
Intron 1 ◽  
Metal Induction

The SpMTA metallothionein gene of the sea urchin Strongylocentrotus purpuratus is regulated developmentally, histospecifically, and by heavy-metal induction. The sequenced 5' flank of the gene can be divided into proximal, middle, and distal regions, each containing a pair of metal response elements (MREs). Canonical 7-bp core sequences are present in all except the middle-region MREs c and d, which contain 1-bp mismatches. Metal-induced expression in transgenic blastulae was increased with each consecutive addition of the middle and distal regions to a chimeric reporter gene construct containing the proximal SpMTA promoter region. Reduced metal induction through point mutation of the distal MREs e and f indicated that the MREs themselves were largely responsible for the transcriptional increase. These activities were further enhanced by SpMTA intron 1, but not when a specific interior region of the intron had been deleted. The atypical MREs c and d did not support induction by themselves, i.e., when present alone with mutated proximal MREs a and b. However, in the presence of intron 1, they were able to substitute for the nullified MREs a and b in the promotion of metal-induced expression. This capability suggests, furthermore, that these atypical MREs, in addition to responding to an intron 1 region, participate cooperatively with the canonical proximal MREs.

scholarly journals Combinatorial regulation by promoter and intron 1 regions of the metallothionein SpMTA gene in the sea urchin embryo.

1993 ◽  
Vol 13 (2) ◽  
pp. 993-1001 ◽  
Author(s):  
G Bai ◽  
E W Stuebing ◽  
H R Parker ◽  
P Harlow ◽  
M Nemer
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Middle Region ◽  
Interior Region ◽  
Induced Expression ◽  
Combinatorial Regulation ◽  
Response Elements ◽  
Sea Urchin Embryo ◽  
Intron 1 ◽  
Metal Induction

The SpMTA metallothionein gene of the sea urchin Strongylocentrotus purpuratus is regulated developmentally, histospecifically, and by heavy-metal induction. The sequenced 5' flank of the gene can be divided into proximal, middle, and distal regions, each containing a pair of metal response elements (MREs). Canonical 7-bp core sequences are present in all except the middle-region MREs c and d, which contain 1-bp mismatches. Metal-induced expression in transgenic blastulae was increased with each consecutive addition of the middle and distal regions to a chimeric reporter gene construct containing the proximal SpMTA promoter region. Reduced metal induction through point mutation of the distal MREs e and f indicated that the MREs themselves were largely responsible for the transcriptional increase. These activities were further enhanced by SpMTA intron 1, but not when a specific interior region of the intron had been deleted. The atypical MREs c and d did not support induction by themselves, i.e., when present alone with mutated proximal MREs a and b. However, in the presence of intron 1, they were able to substitute for the nullified MREs a and b in the promotion of metal-induced expression. This capability suggests, furthermore, that these atypical MREs, in addition to responding to an intron 1 region, participate cooperatively with the canonical proximal MREs.

scholarly journals Early cyclical changes in polyamine synthesis during sea-urchin development

Development ◽  
1973 ◽  
Vol 30 (1) ◽  
pp. 243-256
Author(s):  
Carol-Ann Manen ◽  
Diane H. Russell
Keyword(s):  
Ornithine Decarboxylase ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Decarboxylase Activity ◽  
Early Cleavage ◽  
Polyamine Synthesis ◽  
Selective Degradation ◽  
Ornithine Decarboxylase Activity ◽  
Cleavage Stages

The polyamines, putrescine, spermidine, and spermine, undergo dramatic cyclical variation in both synthesis and accumulation during the early cleavage stages of sea-urchin development. Ornithine decarboxylase activity (putrescine synthesis) in developing Strongylocentrotus purpuratus exhibits maxima at ½ and 2 h after fertilization; increases in ornithine decarboxylase activity appear to correspond to the first and second S phases. Putrescine-stimulated S-adenosyl-l-methionine decarboxylase (spermidine synthesis) and spermidine-stimulated S-adenosyl-l-methionine decarboxylase (spermine synthesis) activities reflect rises during prophase-metaphase of the first and second divisions in two species of sea urchins. Cyclical changes in the concentrations of these three amines were evident also. In general, there were drops in the levels of the amines prior to cleavage. These rapid declines in polyamine concentrations may reflect (1) selective degradation or (2) selective secretion.

Sign in / Sign up

Export Citation Format

Share Document