Identification of Nerve Plexi in Connective Tissues of the Sea CucumberHolothuria glaberrimaby Using a Novel Nerve-Specific Antibody

Abstract

The echinoderm nervous system is one of the least studied among invertebrates, partly because the tools available to study the neurobiology of this phylum are limited. We have now produced a monoclonal antibody (RN1) that labels a nervous system component of the sea cucumber Holothuria glaberrima. Western blots show that our antibody recognizes a major band of 66 kDa and a minor band of 53 kDa. Immunohistological experiments show that, in H. glaberrima, the antibody distinctly labels most of the known nervous system structures and some components that were previously unknown or little studied. A surprising finding was the labeling of nervous plexi within the connective tissue compartments of all organs studied. Double labeling with holothurian neuropeptides and an echinoderm synaptotagmin showed that RN1 labeled most, if not all, of the fibers labeled by these neuronal markers, but also a larger component of cells and fibers. The presence of a distinct connective tissue plexus in holothurians is highly significant since these organisms possess mutable connective tissues that change viscosity under the control of the nervous system. Therefore, the cells and fibers recognized by our monoclonal antibodies may be involved in controlling tensility changes in echinoderm connective tissue.

A START-domain-containing protein is a novel marker of nervous system components of the sea cucumber Holothuria glaberrima

“…Thus, estimation of protein expression was only carried out by normalizing to total protein concentration loaded. However, our results are in agreement with previous characterization of RN1 immunoreactivity in the connective tissue and nerve plexi in the tissues included in this report (Díaz-Balzac et al, 2007). …”

“…Immunohistochemistry was used to compare the expression of STARD10 and RN1 as described before (Diaz-Balzac et al 2007). RN1 ascites fluid was used at a 1/300,000 concentration, while STARD10 antiserum was used at 1/200.…”

“…One of the markers in the second group is a monoclonal antibody, RN1, developed in our laboratory that labels most of the nervous components of the nervous system of sea cucumbers or holothurians, members of the Class Holothuroidea within the Echinodermata phylum (Diaz-Balzac, 2007). In the sea cucumber Holothuria glaberrima, RN1 labels all previously described nervous structures including the ectoneural and hyponeural divisions plus many previously undescribed components such as large fiber plexi and cells within many organs and tissues (Diaz-Balzac et al 2007).…”

“…In the sea cucumber Holothuria glaberrima, RN1 labels all previously described nervous structures including the ectoneural and hyponeural divisions plus many previously undescribed components such as large fiber plexi and cells within many organs and tissues (Diaz-Balzac et al 2007). These nervous structures also show positive immunostaining to neuropeptides and other markers of neural components (Diaz-Balzac, 2007, 2014). …”

Gonad-stimulating substance-like molecule from the radial nerve of the sea cucumber

“…Elphick et al, 1995;Byrne et al, 2005), sea cucumbers (e.g. Garcia-Arraras et al, 1991;Diaz-Miranda et al, 1995;Inoue et al, 2002;Byrne et al, 2006: Diaz-Balzac et al, 2007Bishop and Burke, 2007), and brittle stars (de Bremaeker et al, 1997;Hirokawa et al, 2008), mainly by introducing immunochemistry using antibodies raised against various neurotransmitters or anti-synaptotagmin monoclonal antibody, and molecular biology.…”