Hemicentrotus
Sea Urchins
Molecular Sequence Data
A switch in the cellular basis of skeletogenesis in late-stage sea urchin larvae. (1/11)
Primary mesenchyme cells (PMCs) are solely responsible for the skeletogenesis during early larval development of the sea urchin, but the cells responsible for late larval and adult skeletal formation are not clear. To investigate the origin of larval and adult skeletogenic cells, I first performed transplantation experiments in Pseudocentrotus depressus and Hemicentrotus pulcherrimus, which have different skeletal phenotypes. When P. depressus PMCs were transplanted into H. pulcherrimus embryos, the donor phenotype was observed only in the early larval stage, whereas when secondary mesenchyme cells (SMCs) were transplanted, the donor phenotype was observed in late and metamorphic larvae. Second, a reporter construct driven by the spicule matrix protein 50 (SM50) promoter was introduced into fertilized eggs and their PMCs/SMCs were transplanted. In the resultant 6-armed pluteus, green fluorescent protein (GFP) expression was observed in both PMC and SMC transplantations, suggesting SMC participation in late skeletogenesis. Third, transplanted PMCs or SMCs tagged with GFP were analyzed by PCR in the transgenic chimeras. As a result, SMCs were detected in both larval and adult stages, but GFP from PMCs was undetectable after metamorphosis. Thus, it appears that SMCs participate in skeletogenesis in late development and that PMCs disappear in the adult sea urchin, suggesting that the skeletogenesis may pass from PMCs to SMCs during the late larval stage. (+info)Real-time monitoring of functional interactions between upstream and core promoter sequences in living cells of sea urchin embryos. (2/11)
There are some functional compatibilities between upstream and core promoter sequences for transcriptional activation in yeast, Drosophila and mammalian cells. Here we examined whether similar compatibilities exist in sea urchin embryos, and if so, whether they are dynamically regulated during early development. Two reporter plasmids, each containing a test promoter conjugated to either CFP or YFP, were concurrently introduced into embryos, and their expression patterns were studied by fluorescence microscopy. The upstream sequence of the Hemicentrotus pulcherrimus (Hp) OtxE promoter drives the expression of its own core promoter and that of Strongylocentrotus purpuratus (Sp) Spec2a in different embryonic regions, especially at the late gastrula stage. Interestingly, when the four putative transcription factor binding sites of this upstream sequence were individually mutated, the resulting sequences directed different spatiotemporal expression from the same set of two core promoters, indicating that combinations of upstream factors may determine core promoter usage in sea urchin embryos. In addition, the insertion or deletion of consensus or nonconsensus TATA sequences changed the expression profile significantly, irrespective of whether the upstream sequence was intact or mutated. Thus, the TATA sequence may serve as a primary determinant for core promoter selection in these cells. (+info)DNA variations within the sea urchin Otx gene enhancer. (3/11)
We performed both intra- and interspecific comparisons of the Otx gene in the sea urchin to investigate DNA variations within the enhancer elements. Intraspecific comparisons within Hemicentrotus pulcherrimus showed that indel variations were rare within the Otx enhancer, whereas SNP variations were found uniformly within the whole test region. A similar pattern of DNA variation was observed in comparisons between closely related species. On the other hand, both nucleotide substitution and indel variations were at high levels between distant species. Additionally, the regions corresponding to the Otx enhancer in two related species showed substantial activities during development. Our results suggest the possibility that a stabilizing selection has occurred during the evolution of the Otx gene enhancer in the sea urchin that maintains its expression pattern. (+info)Spatio-temporal expression of a Netrin homolog in the sea urchin Hemicentrotus pulcherrimus (HpNetrin) during serotonergic axon extension. (4/11)
(+info)Development of a dopaminergic system in sea urchin embryos and larvae. (5/11)
(+info)ankAT-1 is a novel gene mediating the apical tuft formation in the sea urchin embryo. (6/11)
(+info)Zinc finger homeobox is required for the differentiation of serotonergic neurons in the sea urchin embryo. (7/11)
(+info)Development of the GABA-ergic signaling system and its role in larval swimming in sea urchin. (8/11)
(+info)I'm sorry for any confusion, but "Hemicentrotus" is not a medical term. It is the genus name of a group of sea urchins, including the Pacific Sea Urchin (Hemicentrotus pulcherrimus), which are commonly studied in biological research. They are not associated with human health or disease.
I'm happy to help! However, it seems there might be a bit of confusion here. "Sea urchins" is a common name that refers to a type of marine invertebrate animal, typically characterized by their round, spiny shells. They belong to the class Echinoidea within the phylum Echinodermata.
Medically speaking, there isn't a specific definition for "sea urchins." However, if you come into contact with sea urchins while swimming or diving and accidentally step on them, their spines can puncture your skin and potentially cause an infection. In this case, medical attention may be necessary to remove the embedded spines and treat any resulting infection.
If you were referring to a specific medical term related to sea urchins, could you please clarify? I'm here to help!
An ovum is the female reproductive cell, or gamete, produced in the ovaries. It is also known as an egg cell and is released from the ovary during ovulation. When fertilized by a sperm, it becomes a zygote, which can develop into a fetus. The ovum contains half the genetic material necessary to create a new individual.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.