Cloning, sequencing of bone morphogenetic protein from sea urchin, Hemicentrotus pulcherrimus.

A cDNA coding for bone morphogenetic protein (BMP) homolog of the sea urchin, Hemicentrotus pulcherrimus, was isolated from mid-gastrula using reverse transcription-polymerase chain reaction (RT-PCR) technique. The 2314 nucleotide sequence contains a 1383 open reading frame corresponding to a translation product of 461 amino acids. Comparison of the nucleotide and deduced amino acid sequence with BMP isolated from Strongylocentrotus purpuratus (SpBMP5-7; accession No. Z48313) shows a high degree of conservation. HpBMP seems to belong to the 60A subgroup as a result. A mRNA coding H. pulcherrimus BMP (HpBMP) was not detected in the unfertilized egg, but it was detected from blastula to prism stages.

Mitochondrial Protein Synthesis During Embryonic Development of Cricket: (cricket embryo/mitochondria/protein synthesis/protease).

Protein synthetic activity in homogenate of embryos of cricket, Gryllus bimaculatus, increased transiently 25 hr after oviposition, though the activity in mitochondrial fraction increased successively thereafter. The decrease in the activity after the peak in homogenate was caused apparently by increase in the amino acid content in cytosol during development. To analyze increase in the mitochondrial protein synthetic activity 25 hr after oviposition, effect of various components was examined in the reconstituted mitochondrial system. The nucleic acids extracted from 25-hr embryos most effectively stimulated the protein synthetic activity, but those from 0-hr embryos did not. The results were discussed on the role of mitochondrial protein synthesis during development of cricket embryos.

Stimulation of Protein Synthesis in the Mitochondria of Sea Urchin Embryos before Gastrulation: (protein synthesis/sea urchin embryo/mitochondria/peptide elongation factor/mitosol).

A transient increase in protein synthesis was observed in mitochondria at the mesenchyme blastula stage of sea urchin (Hemicentrotus pulcherrimus) embryos. This stimulated activity was inhibited by chloramphenicol but not by cycloheximide. Reconstituting experiments in which poly U-dependent protein synthesis was carried out showed the mitochondrial peptide elongation factor to be essential for increasing the protein synthetic activity in mesenchyme blastula, but aminoacyl tRNA synthetase and ribosome fraction containing initiation factor not to be involved in this increase. These findings are discussed in relation to the differentiation of embryos at the gastrulation stage.

Changes in Osmotic Pressure and Swelling in Horseshoe Crab Embryos During Development: (horseshoe crab embryo/swelling/water influx/perivitelline fluid/osmotic pressure).

Water influx accompanying the swelling of embryos during normal development of horseshoe crabs, Limulus polyphemus and Tachypleus tridentatus, following a rupture of the chorion, was analyzed. The increase in volume of perivitelline fluid during deveopment was about 90 percent of the increase in total embryo weight. Considerable water discharge was observed on drying the embryos in air and a reversible water influx occurred with a second immersion in sea water, even though the embryos died as a result of this treatment. Since the osmotic pressure of the perivitelline fluids decreased markedly during development until the end of swelling, a close correlation between swelling and osmotic pressure was recognized. These results indicate that certain osmoactive substances may be produced in the perivitelline fluid at the initial stage of swelling.