Biomedical subjects

Naoaki Sugiura

Publications and source records attributed to Naoaki Sugiura.

3 recordsLinked to original sources

PubMed2004

NARG2 encodes a novel nuclear protein with (S/T)PXX motifs that is expressed during development.

We previously identified a partial expressed sequence tag clone corresponding to NARG2 in a screen for genes that are expressed in developing neurons and misexpressed in transgenic mice that lack functional N-methyl-d-aspartate receptors. Here we report the first characterization of the mouse and human NARG2 genes, cDNAs and the proteins that they encode. Mouse and human NARG2 consist of 988 and 982 amino acids, respectively, and share 74% identity. NARG2 does not display significant homology to other known genes, and lower organisms such as Saccharomyces cerevisiae, Drosophila melanogaster and Fugu rubripes appear to lack NARG2 orthologs. In vitro translation of the mouse cDNA yields a 150 kDa protein. NARG2 localizes to the nucleus in transfected cells, and deletion of a canonical basic nuclear localization signal suggests that this and other sequences in the protein cooperate for nuclear targeting. NARG2 consists of 16 exons in both mice and humans, 11 of which are identical in length, and alternative splicing is evident in both species. Exon 10 is the largest, and exhibits a much higher rate of nonsynonymous nucleotide substitution than the others. In addition, NARG2 contains (S/T)PXX motifs (11 in mouse NARG2, six in human NARG2). Northern blot analysis and RNase protection demonstrated that NARG2 is expressed at relatively high levels in dividing and immature cells, and that it is down-regulated upon terminal differentiation. The results indicate that NARG2 encodes a novel (S/T)PXX motif-containing nuclear protein, and suggest that NARG2 may play an important role in the early development of a number of different cell types.

Amino Acid Sequence↗

PubMed2003

An evolutionarily conserved N-terminal acetyltransferase complex associated with neuronal development.

We previously identified mNAT1 (murine N-terminal acetyltransferase 1) as an embryonic gene that is expressed in the developing brain and subsequently down-regulated, in part, by the onset of N-methyl-d-aspartate (NMDA) receptor function. By searching the data base we discovered a second closely related gene, mNAT2. mNAT1 and mNAT2 are highly homologous to yeast NAT1, a gene known to regulate entry into the G0 phase of the cell cycle. However, in the absence of further characterization, including evidence that mammalian homologues of NAT1 encode functional acetyltransferases, the significance of this relationship has been unclear. Here we focus on mNAT1. Biochemical analysis demonstrated that mNAT1 and its evolutionarily conserved co-subunit, mARD1, assemble to form a functional acetyltransferase. Transfection of mammalian cells with mNAT1 and mARD1 followed by immunofluorescent staining revealed that these proteins localize to the cytoplasm in both overlapping and separate compartments. In situ hybridization demonstrated that throughout brain development mNAT1 and mARD1 are highly expressed in areas of cell division and migration and are down-regulated as neurons differentiate. Finally, mNAT1 and mARD1 are expressed in proliferating mouse P19 embryonic carcinoma cells; treatment of these cells with retinoic acid initiates exit from the cell cycle, neuronal differentiation, and down-regulation of mNAT1 and mARD1 as the NMOA receptor 1 gene is induced. The results provide the first direct evidence that vertebrate homologues of NAT1 and ARD1 form an evolutionarily conserved N-terminal acetyltransferase and suggest that expression and down-regulation of this enzyme complex plays an important role in the generation and differentiation of neurons.

Acetyltransferases↗

PubMed2003

Interaction of NF-Y with the 3'-flanking DNA sequence of the CCAAT box.

NF-Y, also referred to as CCAAT-binding factor, is a major CCAAT-binding transcription factor. The present study demonstrated that the 3'-flanking region of the CCAAT box is involved in the formation of a stable NF-Y.DNA complex. An electrophoretic mobility shift assay showed that the interaction of NF-Y with DNA 15 bp downstream of the CCAAT box alters not only the affinity of NF-Y for its binding site but also the electrophoretic mobility of the NF-Y.DNA complex. This interaction is accompanied by a conformational change of NF-Y as demonstrated by a change in the reactivity of an anti-NF-YA antibody to the NF-Y.DNA complex.

Animals↗