Our understanding of the genes involved in Alzheimer's disease (AD) is incomplete. Using subtractive cloning technology, we discovered that the alpha/beta-hydrolase fold protein gene NDRG2 (NDRG family member 2) is upregulated at both the RNA and protein levels in AD brains. Expression of NDRG2 in affected brains was revealed in (1) cortical pyramidal neurons, (2) senile plaques and (3) cellular processes of dystrophic neurons. Overexpression of two splice variants encoding a long and short NDRG2 isoform in hippocampal pyramidal neurons of transgenic mice resulted in localization of both isoforms to dendritic processes. Taken together, our findings suggest that NDRG2 upregulation is associated with disease pathogenesis in the human brain and provide new insight into the molecular changes that occur in AD.
Title: Tissue specific basal expression of soluble murine epoxide hydrolase and effects of clofibrate on the mRNA levels in extrahepatic tissues and liver Johansson C, Stark A, Sandberg M, Ek B, Rask L, Meijer J Ref: Archives of Toxicology, 70:61, 1995 : PubMed
The soluble epoxide hydrolase mRNA level in liver was increased eight-fold upon administration of the hypolipidemic drug and peroxisome proliferator clofibrate for 7 days to mice. The soluble epoxide hydrolase mRNA was back at control levels within 1-2 days after clofibrate withdrawal. The highest expression was in liver, intestine and kidney. Lower levels were found in heart and muscle and very low levels were found in testes, lung, brain and spleen. The mRNA levels were increased in liver, kidney and heart by clofibrate.
Four cDNA clones, pDR-alpha-1, pDR-alpha-2, pDR-alpha-3 and pDR-alpha-4, corresponding to the alpha chain of HLA-DR antigens, have been sequenced. Restriction maps and sequences suggest that all clones are identical apart from a single-base substitution present in pDR-alpha-1. Amino acid sequence data, together with the nucleotide sequence data, allowed the complete amino acid sequence to be predicted. The alpha chain is composed of 229 amino acids, of which 191 are exposed on the outside of the plasma membrane. The membrane-embedded portion of the chain consists of 23 hydrophobic amino acids. The succeeding 15 amino acids form the cytoplasmically localized hydrophilic tail. The extracellular portion, with carbohydrate moieties linked to Asn78 and Asn118, seems to be organized into two domains. The second domain, which contains the only disulfide bond of the alpha chain, displays amino acid sequence homology to immunoglobulin constant regions, to the second domain of the beta chain of a class II antigen, to the third domain of heavy chains of class I antigens and to beta 2-microglobulin. Thus the subunits of immunoglobulins, class I antigens and class II antigens are related evolutionarily.
Title: Complete amino acid sequence of an HLA-DR antigen-like beta chain as predicted from the nucleotide sequence: similarities with immunoglobulins and HLA-A, -B, and -C antigens Larhammar D, Schenning L, Gustafsson K, Wiman K, Claesson L, Rask L, Peterson PA Ref: Proc Natl Acad Sci U S A, 79:3687, 1982 : PubMed
The complete nucleotide sequence of an HLA-DR antigen-like beta-chain cDNA clone was determined. The 1,080 base pairs include the complete coding region and most of the untranslated portion. The predicted amino acid sequence has 229 residues. The beta chain contains two immunoglobulin-like disulfide loops and a 21-amino acid residue membrane-integrated segment. Ten amino acid residues reside on the cytoplasmic side of the plasma membrane. The single asparagine-linked carbohydrate moiety is attached to asparagine-19. The NH2-terminal 91 residues of the beta chain are homologous to the corresponding region of HLA-A, -B, and -C antigen heavy chains. Residues 92-192 of the beta chain display statistically significant homology to members of the immunoglobulin family, beta 2-microglobulin, and the immunoglobulin-like domain of HLA-A, -B, and -C antigen heavy chains. These data establish that the major histocompatibility antigens of class I and class II type and the constant regions of immunoglobulins are evolutionarily related.
The HLA-D locus in the major histocompatibility complex controls the expression of the genetically polymorphic HLA-DR antigens. mRNA coding for the beta chains of these antigens was partially purified from the human lymphoblastoid cell line Raji. The mRNA was copied into double-stranded cDNA and cloned in Escherichia coli. One clone, pDR-beta-1, obtained by hybrid selection, carries a 1070-base-pair insert comprising all of the coding region except the signal sequence and a substantial portion of the untranslated region. To identify pDR-beta-1, highly purified HLA-DR antigen beta chains derived from Raji cells were subjected to NH2-terminal amino acid sequence determination. This sequence displayed extensive homology with that deduced from the nucleotide sequence at the 5' end of the pDR-beta-1 coding region. Taken together, the amino acid and nucleotide sequences strongly argue in favor of Raji cells containing at least two beta-chain loci.
mRNA coding for mouse major transplantation antigens of the d haplotype was partially purified, copied into double-stranded cDNA, and cloned in Escherichia coli. Clones were selected by their ability to hybridize specifically with mRNA coding for H-2K, D, or L antigens. One of these clones, pH-2d-1, carries a 1200-base-pair insert, comprising the noncoding region, including poly(A) at the 3' end and part of the coding region. A partial sequence of the latter region showed extensive homology with the known amino acid sequences of H-2Kb,Kk, and HLA-B7 antigens. From this comparison, it appears that the coding region extends from amino acid 133 in the second domain, through the third domain, to the cytoplasmic COOH-terminal region. A stretch of 24 hydrophobic or uncharged residues, located 31 amino acids from the COOH-terminal end, could represent the segment that spans the membrane. This is followed on the cytoplasmic side of the membrane by a cluster of basic amino acids and a possible phosphorylation site on a threonine residue.
cDNA for a beta-chain of HLA-DR antigens was cloned and the partial nucleotide sequence was determined. The data suggest that the beta-chain consists of approximately 230 amino acids, of which about 200 are exposed on the cell surface. The beta-chain appears to be composed of two exposed disulphide-containing domains. The arrangement of the disulphide loops suggests that the beta-chain is similar in structure to the HLA-A, B, C antigen subunits and the immunoglobulin chains. For the beta-chain domain closest to the membrane this similarity was verified at the level of primary structure. The partial amino acid sequence of the NH2-terminal domain did not display any apparent homology to HLA-A, B, C antigens and immunoglobulins. However, the similarity established here between the two types of major histocompatibility antigen subunits and the immunoglobulin chains suggests a common ancestral origin for at least some regions of these molecules.
