Martin Nemer

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Calreticulin is a multifunctional protein that acts as a major Ca(2+)-binding (storage) protein in the lumen of the endoplasmic reticulum. It is also found in the nucleus, suggesting that it may have a role in transcription regulation. Calreticulin has been reported to bind to the synthetic peptide KLGFFKR, which is almost identical to an amino-acid(More)
Rapidly labeled RNA from four-cell embryos and blastulae of sea urchins was analyzed by sedimentation and for ability to form DNA-RNA hybrids. The RNA was derived from polyribosomes and from the "gel interphase," an extraction compartment resulting from treatment of whole embryos with phenol and known to be enriched with nuclei. The RNA from both sources(More)
A cDNA of the sea urchin Strongylocentrotus purpuratus was identified as encoding polyubiquitin and used to detect a single gene with transcripts containing multiple ubiquitin coding units. Polyubiquitin transcripts exist as a 3.2-kb RNA in polyribosomes and as three higher molecular weight RNAs in purified nuclei. The amount of polyubiquitin RNA is(More)
Early stage treatment of the sea urchin embryo with zinc ions is known to prevent its gastrulation. The treated embryo, termed "animalized" and classically regarded as a permanent blastula with possibly exaggerated ectodermal differentiation, can be viewed, instead, as being in a state of reversibly suspended differentiation. This proposition is supported(More)
It is shown that self-supporting graphitic structures of specific shape can be grown in a variety of forms, from nanoscale to macroscale, on metal templates, in a fuel-rich mixture of ethylene and oxygen at temperatures between 750 and 900 K. The evidence presented suggests graphite can be grown in any shape created from catalytic metals (e.g., Ni) under(More)
The metallothioneins (MTs) constitute a diverse family of proteins, which are enriched in cysteines and bind heavy metals. The amino acid sequence of sea urchin MT has been obtained from its mRNA sequence and compared with MT sequences of various sources. A largely conserved sequence of 10 amino acids, the "central segment," is located near the center of(More)
Sea urchin embryo metallothionein (MT) mRNAs MTa and MTb have distinct cDNA sequences and are transcripts of different genes of a multigene family. These MT mRNAs differ in size and in their 3'-untranslated sequences. They encode proteins that are unusual among MT isotypes in that the relative positions of their cysteine residues are partially out of(More)
beta-Tubulin mRNAs associated with cilium formation in Strongylocentrotus purpurpatus sea urchin embryos are expressed selectively from a multiple gene family. The accumulations of three beta-tubulin mRNAs (beta 1, beta 2, and beta 3) are temporally coordinated with ciliogenesis during blastula development and with the regeneration of cilia after their(More)
A library of cDNA clones was constructed representing polysomal polyadenylated RNA of mesenchyme blastulae of Strongylocentrotus purpuratus. Using this library, we determined whether or not individual RNA species are associated with animalization of embryos by zinc ions. Clones corresponding to the most actively synthesized RNAs during the period just prior(More)
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(More)