scholarly journals Organization and evolution of the actin gene family in sea urchins.

1983 ◽  
Vol 3 (10) ◽  
pp. 1824-1833 ◽  
Author(s):  
P J Johnson ◽  
D R Foran ◽  
G P Moore

Genomic libraries of the sea urchins Strongylocentrotus franciscanus and Lytechinus pictus were screened with an actin cDNA clone from Strongylocentrotus purpuratus. Four nonoverlapping clones were isolated and characterized from the S. franciscanus library; three were isolated and characterized from the L. pictus library. Linked genes having the same transcriptional orientation were found on all S. franciscanus clones. Three clones contained two actin genes each; the other clone contained three. In contrast, the L. pictus clones contained only one actin gene. Comparison of actin genomic clones from these three species indicated a difference in the genomic organization of sea urchin actin genes in that the genes appear to be more highly clustered in S. franciscanus than in S. purpuratus and L. pictus. Genomic dot blots and reassociation kinetics demonstrated that the copy number of actin genes in all three species is 15 to 20. Nucleotide sequence homology of actin genes within and among the species was measured by thermal elution. These experiments indicated that there is a high degree of interspecies actin gene sequence homology but that, within each species, actin gene sequences may differ by as much as 30%. Sequencing of two S. franciscanus actin genes revealed introns at the same amino acid positions, 121 and 204, reported for S. purpuratus actin genes. These data demonstrated that the genomic copy number, the transcriptional orientation of linked genes, and, to the extent studied, the intron position of actin genes have evolved similarly in these three species. In contrast, significant change has occurred in the chromosomal arrangement of sea urchin actin genes.

1983 ◽  
Vol 3 (10) ◽  
pp. 1824-1833
Author(s):  
P J Johnson ◽  
D R Foran ◽  
G P Moore

Genomic libraries of the sea urchins Strongylocentrotus franciscanus and Lytechinus pictus were screened with an actin cDNA clone from Strongylocentrotus purpuratus. Four nonoverlapping clones were isolated and characterized from the S. franciscanus library; three were isolated and characterized from the L. pictus library. Linked genes having the same transcriptional orientation were found on all S. franciscanus clones. Three clones contained two actin genes each; the other clone contained three. In contrast, the L. pictus clones contained only one actin gene. Comparison of actin genomic clones from these three species indicated a difference in the genomic organization of sea urchin actin genes in that the genes appear to be more highly clustered in S. franciscanus than in S. purpuratus and L. pictus. Genomic dot blots and reassociation kinetics demonstrated that the copy number of actin genes in all three species is 15 to 20. Nucleotide sequence homology of actin genes within and among the species was measured by thermal elution. These experiments indicated that there is a high degree of interspecies actin gene sequence homology but that, within each species, actin gene sequences may differ by as much as 30%. Sequencing of two S. franciscanus actin genes revealed introns at the same amino acid positions, 121 and 204, reported for S. purpuratus actin genes. These data demonstrated that the genomic copy number, the transcriptional orientation of linked genes, and, to the extent studied, the intron position of actin genes have evolved similarly in these three species. In contrast, significant change has occurred in the chromosomal arrangement of sea urchin actin genes.


1988 ◽  
Vol 18 (12) ◽  
pp. 1595-1602 ◽  
Author(s):  
J. R. Kenny ◽  
B. P. Dancik ◽  
L. Z. Florence ◽  
F. E. Nargang

We have determined the nucleotide sequence of the carboxy-terminal portion of an actin gene (PAc1-A) isolated from Pinuscontorta var. latifolia (Engelm.). Pairwise comparisons of both nucleotide and deduced amino acid sequences were made among PAc1-A, the soybean actins SAc3 and SAc1, maize actin MAc1, chicken β-actin, and yeast β-actin. Of the other actins SAc3 was most similar to the PAc1-A amino acid sequence (91.3% identity) and yeast actin the least similar (78.3% identity). The intron in PAc1-A is present at the same location as the third intron found in MAc1, SAc1, and SAc3 actin genes. This conservation of intron position is unusual when compared with nonplant actin genes.


1981 ◽  
Vol 1 (7) ◽  
pp. 609-628 ◽  
Author(s):  
R H Scheller ◽  
L B McAllister ◽  
W R Crain ◽  
D S Durica ◽  
J W Posakony ◽  
...  

A set of at least 11 actin genes has been isolated from genomic recombinant deoxyribonucleic acid libraries of the sea urchin Strongylocentrotus purpuratus. Most of the isolates derive from a library which represents the genome of a single animal. There are at least five distinct types of sea urchin actin gene, some of which are represented by multiple copies in the genome. The actin gene types are distinguished by nonhomologous flanking sequences and intervening sequences, though the protein coding sequences appear in most cases to be quite similar. Eight of the 11 genes isolated have been recovered in lambda recombinants that contain two actin genes, linked at 5- to 9-kilobase distances. Restriction map overlaps suggest that the genome contains an array of at least three of these genes spaced over about 30 kilobases of deoxyribonucleic acid. In the linkage patterns observed, actin genes of diverse types were linked to each other. In early embryos, actin messenger ribonucleic acid (RNA) transcripts of 1.8 and 2.2 kilobases were found, and the longer of these transcripts was more prevalent in the maternal RNA of the egg. From RNA gel blot experiments, we conclude that the two transcripts derive from different actin gene types. Different repetitive sequences were located to either side of most of the actin genes, and in most observed cases the repeat sequences which were adjacent to actin genes of a given type were similar. The repeat sequences flanking the actin genes belonged to families which were transcribed, but those repeats in the neighborhood of the actin genes which have been investigated were not themselves represented in the stable RNAs of eggs or early embryos.


Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 259-272 ◽  
Author(s):  
C.R. Tomlinson ◽  
M.T. Kozlowski ◽  
W.H. Klein

The Spec gene family of Stronglyocentrotus purpuratus is expressed exclusively in aboral ectoderm cells during embryogenesis. To investigate the regulation of Spec gene activity, the region around the Spec1 transcriptional initiation site was analyzed for sites of protein-DNA interaction. One high-affinity site bound a factor termed SpF1 within the Spec1 5′ untranslated leader region at position +39 to +60. The core sequence recognized by SpF1, CACGTG, is the same as that of the upstream stimulatory factor (USF), a widely occurring vertebrate transcription factor containing a myc-HLH motif. A comparison of USF- and SpF1-binding activities suggested that SpF1 was a sea urchin version of USF. SpF1 activity was detectable only in ectoderm cells of the embryo, implying that it has a role as a cell type-specific transcription factor. SpF1-binding sites were also found upstream of the Spec2a and Spec2c genes in the same conserved sequence block as Spec1. Extracts from Lytechinus pictus embryos showed an SpF1-like activity, suggesting that SpF1 is conserved in sea urchins. Surprisingly, changes in the Spec1, Spec2a, or Spec2c genes that removed or modified the SpF1-binding site had no effect on expression when reporter gene fusions containing these mutations were injected into sea urchin eggs and analyzed for expression during embryogenesis. We propose that, while SpF1 may not be essential for expression of the exogenously introduced reporter genes, it may be required for proper regulation of the endogenous Spec genes.


1984 ◽  
Vol 4 (5) ◽  
pp. 840-845 ◽  
Author(s):  
R Garcia ◽  
B Paz-Aliaga ◽  
S G Ernst ◽  
W R Crain

The expression of three different actin genes in the sea urchin, Strongylocentrotus purpuratus, was monitored in embryos and adult tissues by using untranslated mRNA sequences as specific hybridization probes. Three distinct patterns of expression were found: muscle specific, embryo specific, and constitutive (i.e., present in all tissues examined). The actin genes encoding the muscle-specific and constitutively expressed genes were each found to be present once in the haploid genome. The embryo-specific probe could derive from either a single gene or a small subset of actin genes. These data demonstrate that at least three members of the sea urchin actin gene family are expressed in distinct ways and thus are probably associated with different regulatory programs of gene expression necessary for development of this metazoan.


Zygote ◽  
2015 ◽  
Vol 24 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Jing Liang ◽  
Heghush Aleksanyan ◽  
Stan Metzenberg ◽  
Steven B. Oppenheimer

SummaryThe sea urchin embryo is recognized as a model system to reveal developmental mechanisms involved in human health and disease. In Part I of this series, six carbohydrates were tested for their effects on gastrulation in embryos of the sea urchin Lytechinus pictus. Only l-rhamnose caused dramatic increases in the numbers of unattached archenterons and exogastrulated archenterons in living, swimming embryos. It was found that at 30 h post-fertilization the l-rhamnose had an unusual inverse dose-dependent effect, with low concentrations (1–3 mM) interfering with development and higher concentrations (30 mM) having little to no effect on normal development. In this study, embryos were examined for inhibition of archenteron development after treatment with α-l-rhamnosidase, an endoglycosidase that removes terminal l-rhamnose sugars from glycans. It was observed that the enzyme had profound effects on gastrulation, an effect that could be suppressed by addition of l-rhamnose as a competitive inhibitor. The involvement of l-rhamnose-containing glycans in sea urchin gastrulation was unexpected, since there are no characterized biosynthetic pathways for rhamnose utilization in animals. It is possible there exists a novel l-rhamnose-containing glycan in sea urchins, or that the enzyme and sugar interfere with the function of rhamnose-binding lectins, which are components of the innate immune system in many vertebrate and invertebrate species.


Zygote ◽  
2008 ◽  
Vol 16 (4) ◽  
pp. 355-361 ◽  
Author(s):  
Azalia Contreras ◽  
John Vitale ◽  
Virginia Hutchins-Carroll ◽  
Edward J. Carroll ◽  
Steven B. Oppenheimer

SummaryHyalin is a large glycoprotein, consisting of the hyalin repeat domain and non-repeated regions, and is the major component of the hyaline layer in the early sea urchin embryo of Strongylocentrotus purpuratus. The hyalin repeat domain has been identified in proteins from organisms as diverse as bacteria, sea urchins, worms, flies, mice and humans. While the specific function of hyalin and the hyalin repeat domain is incompletely understood, many studies suggest that it has a functional role in adhesive interactions. In part I of this series, we showed that hyalin isolated from the sea urchin S. purpuratus blocked archenteron elongation and attachment to the blastocoel roof occurring during gastrulation in S. purpuratus embryos, (Razinia et al., 2007). The cellular interactions that occur in the sea urchin, recognized by the U.S. National Institutes of Health as a model system, may provide insights into adhesive interactions that occur in human health and disease. In part II of this series, we showed that S. purpuratus hyalin heterospecifically blocked archenteron–ectoderm interaction in Lytechinus pictus embryos (Alvarez et al., 2007). In the current study, we have isolated hyalin from the sea urchin L. pictus and demonstrated that L. pictus hyalin homospecifically blocks archenteron–ectoderm interaction, suggesting a general role for this glycoprotein in mediating a specific set of adhesive interactions. We also found one major difference in hyalin activity in the two sea urchin species involving hyalin influence on gastrulation invagination.


1981 ◽  
Vol 1 (7) ◽  
pp. 609-628
Author(s):  
R H Scheller ◽  
L B McAllister ◽  
W R Crain ◽  
D S Durica ◽  
J W Posakony ◽  
...  

A set of at least 11 actin genes has been isolated from genomic recombinant deoxyribonucleic acid libraries of the sea urchin Strongylocentrotus purpuratus. Most of the isolates derive from a library which represents the genome of a single animal. There are at least five distinct types of sea urchin actin gene, some of which are represented by multiple copies in the genome. The actin gene types are distinguished by nonhomologous flanking sequences and intervening sequences, though the protein coding sequences appear in most cases to be quite similar. Eight of the 11 genes isolated have been recovered in lambda recombinants that contain two actin genes, linked at 5- to 9-kilobase distances. Restriction map overlaps suggest that the genome contains an array of at least three of these genes spaced over about 30 kilobases of deoxyribonucleic acid. In the linkage patterns observed, actin genes of diverse types were linked to each other. In early embryos, actin messenger ribonucleic acid (RNA) transcripts of 1.8 and 2.2 kilobases were found, and the longer of these transcripts was more prevalent in the maternal RNA of the egg. From RNA gel blot experiments, we conclude that the two transcripts derive from different actin gene types. Different repetitive sequences were located to either side of most of the actin genes, and in most observed cases the repeat sequences which were adjacent to actin genes of a given type were similar. The repeat sequences flanking the actin genes belonged to families which were transcribed, but those repeats in the neighborhood of the actin genes which have been investigated were not themselves represented in the stable RNAs of eggs or early embryos.


1984 ◽  
Vol 4 (5) ◽  
pp. 840-845
Author(s):  
R Garcia ◽  
B Paz-Aliaga ◽  
S G Ernst ◽  
W R Crain

The expression of three different actin genes in the sea urchin, Strongylocentrotus purpuratus, was monitored in embryos and adult tissues by using untranslated mRNA sequences as specific hybridization probes. Three distinct patterns of expression were found: muscle specific, embryo specific, and constitutive (i.e., present in all tissues examined). The actin genes encoding the muscle-specific and constitutively expressed genes were each found to be present once in the haploid genome. The embryo-specific probe could derive from either a single gene or a small subset of actin genes. These data demonstrate that at least three members of the sea urchin actin gene family are expressed in distinct ways and thus are probably associated with different regulatory programs of gene expression necessary for development of this metazoan.


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