Expression and identification of a new splice variant of neuroglycan C, a transmembrane chondroitin sulfate proteoglycan, in the human brain

Abstract

Neuroglycan C (NGC) is a transmembrane chondroitin sulfate proteoglycan with an EGF module. We studied the expression of NGC in the human brain, mainly in the hippocampus, and confirmed some observations by conducting experiments using rat brain. In humans, NGC mRNA was expressed exclusively in the brain, especially in the immature brain. The telencephalon, including the hippocampus and neocortex, showed strong mRNA expression. NGC was immunolocalized to neuropils in the hippocampus and neocortex of the adult rat. RT-PCR experiments showed that four splice variants (NGC-I, -II, -III, and -IV) were expressed in the adult human hippocampus. By Western blotting, the expression as proteins of all splice variants except NGC-II was confirmed in the adult rat hippocampus. NGC-IV, which was first found in the present study, had the shortest cytoplasmic domain among the four variants. NGC-IV mRNA was expressed by neurons, but not by astrocytes, in culture prepared from the fetal rat hippocampus, suggesting that NGC-IV plays a role specific to neurons. In addition, the human NGC gene, which is registered as CSPG5, comprised six exons and was approximately 19 kb in size. In exon 2, a single nucleotide polymorphism resulting in Val188Gly in the NGC ectodomain was observed.

Identification and Functions of Chondroitin Sulfate in the Milieu of Neural Stem Cells

“…Biotinylated secondary antibodies and a Vectastain ABC elite kit were obtained from Vector Laboratories (Burlingame, CA). The following antibodies were prepared in our laboratory: a monoclonal anti-neurocan antibody (1G2, mouse IgG 1 (19)), a monoclonal anti-phosphacan antibody (6B4, mouse IgM (20)), and a polyclonal anti-neuroglycan C (NGC) antibody (21). Heparin from porcine intestinal mucosa and EGF were purchased from Sigma.…”

Neuroglycan C Is a Novel Midkine Receptor Involved in Process Elongation of Oligodendroglial Precursor-like Cells

“…Four isoforms due to alternative splicing were reported in NGC (25). To know what isoforms were expressed in CG-4 cells, we performed reverse transcription-PCR using primers specific for the rat NGC sequence and single-stranded cDNA prepared from CG-4 cells as a template and isolated cDNA encoding the open reading frame of NGC.…”

“…NGC, also called chicken acidic leucine-rich epidermal growth factor (EGF)-like domain-containing brain protein, is a developmentally regulated part-time proteoglycan (21)(22)(23) and is expressed as isoforms NGC-I, -II, and -III (22)(23)(24). Recently a new isoform, NGC-IV, was identified (25). NGC contains the CS-E structure in the proteoglycan (PG) form (26), to which MK preferentially binds, and the acidic amino acid cluster box (AB) in the middle of the ectodomain (Fig.…”

Perfil de glicosaminoglicanos sulfatados no útero de camundongas durante o ciclo estral

“…Os proteoglicanos (PGs) são formados por um esqueleto protéico, ao qual estão covalentemente ligadas as cadeias de GAGs presentes na matriz extracelular, na superfície celular e na membrana com domínio intracelular [8][9] .…”

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INTRODUÇÃOHá muito os glicosaminoglicanos (GAGs) vêm despertando interesse clínico em todas as áreas da medicina, pois -consoante seu importante papel no reconhecimento celular, na migração, na proliferação e diferenciação celular -estariam direta ou indiretamente envolvidos com tumores, metástases, angiogênese, reações imunológicas, desenvolvimento folicular e infertilidade, entre outros [1][2][3][4][5][6] .A matriz extracelular é um conjunto de agregados supramoleculares constituídos por uma rede molecular contendo colágeno, glicoproteínas, proteoglicanos e GAGs que mantêm as células associadas possibilitando a organização dos tecidos e a sobrevivência celular 7 .Os proteoglicanos (PGs) são formados por um esqueleto protéico, ao qual estão covalentemente ligadas as cadeias de GAGs presentes na matriz extracelular, na superfície celular e na membrana com domínio intracelular [8][9] .Os GAGs possibilitam várias funções, tais como a hidratação dos espaços ao redor das células, formando géis que variam quanto ao tamanho dos poros e a densidade da carga que atua como filtro regulador da passagem de moléculas pelo meio extracelular, ligando fatores de crescimento e outras proteínas que (proestro = 0,854 ± 0,192; estro = 1,073 ± 0,254; metaestro = 1,003 ± 0,255; e diestro = 0,632 ± 0,443 µg/mg). Os resultados de HS foram: proestro = 0,092 ± 0,097; estro = 0,180 ± 0,141; metaestro = 0,091 ± 0,046; e diestro = 0,233 ± 0,147 µg/mg.

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