Expression pattern of iodotyrosine dehalogenase 1 (DEHAL1) during chick ontogeny

Abstract

The iodotyrosine dehalogenase1 (DEHAL1) enzyme is a transmembrane protein that belongs to the nitroreductase family and shows a highly conserved N-terminal domain. DEHAL1 is present in the liver, kidney and thyroid of mammals. DEHAL1 is known to act on diiodotyrosine (DIT) and monoiodotyrosine (MIT), and is involved in iodine recycling in relation to thyroglobulin. Here, we show the distribution of DEHAL1 during gastrulation to neurulation in developing chick. Immunocytochemistry using an anti-serum directed against the N-terminal domain (met 27 -trp 180 fragment) of human DEHAL1 revealed labelled cells in the embryonic ectoderm, embryonic endoderm, neural plate and in the yolk platelets of the chick embryo at gastrulation stage. Distinct DEHAL1 positive cells were located in the presumptive head ectoderm, presumptive neural crest, head mesenchymal cells and in the dorsal, lateral and ventral parts of neural tube during neurulation. Some cells located at the margin of the developing notochord and somites were also DEHAL1-positive. While the functional significance of this observation is not known, it is likely that DEHAL1 might serve as an agent that regulates cell specific deiodination of MIT and DIT before the onset of thyroidal secretion. The presence of DEHAL1 in different components of the chick embryo suggests its involvement in iodine turnover prior to the formation of functional thyroid. KEY WORDS: chick embryo, gastrulation, immunocytochemistry, iodotyrosine dehalogenase 1, neurulationCell proliferation, cell rearrangement and neuronal death play an important role in patterning different regions of the brain (Quick and Serrano, 2007;Vecino et al., 2004; LeDouarin, 2001;Fleming et al., 1997;Weil et al., 1997;Ellis et al., 1991). A range of signaling molecules and their roles have been implicated in vertebrate development (Borgave and Ghaskadbi, 2009; SanchezCalderon et al., 2007;Patwardhan et al., 2004;Waschek et al., 1998;Hallbook et al., 1995;Ernfors et al., 1995;Hyuga et al., 1993). Thyroid hormones are known to play an important role in the early development including neurulation of several vertebrates and previous studies have shown the occurrence of enzymes that are involved in the recycling of Iodine from thyroid hormones (Courtin et al., 2005;Gereben et al., 2004;Geyten et al., 2002;Asteria, 1998;Becker et al., 1997;Rosenkilde and Ussing, 1996).Iodotyrosine dehalogenase 1 (DEHAL1) is a transmembrane protein, localized mainly at the apical pole of thyrocyte in the Int. J. Dev. Biol. 54: 1503-1508 (2010) human thyroid (Gnidehou et al., 2004). DEHAL1 belongs to the nitroreductase family, with a highly conserved N-terminal domain located between Glu 92 and Gly 244 and a putative transmembrane domain between Asn 213 and Gln 229 (Gnidehou et al., 2004). DEHAL1 is quite different from other deiodinases. DEHAL1 acts on diiodotyrosine (L-DIT) and monoiodotyrosine (L-MIT), whereas, deiodinases act on thyroxine (T4) and triiodothyronine (T3) (Solis et al., 2004). The DIT and MIT are released du...

Iodotyrosines Are Biomarkers for Preclinical Stages of Iodine-Deficient Hypothyroidism in Dehal1-Knockout Mice

“…The activity of the endogenous promoter driving trDehal1-β-Gal expression was investigated in the developing thyroid, kidney and liver, sites of reported iodotyrosine deiodinase activity (19). At E13.5, X-Gal labelling was detected in the pre-follicular stage of the thyroid, in tubular structures of the kidneys, and was not detected in the liver (Figure 2A).…”