Masami Nagata

Cloning, expression, and mapping of UBE2I, a novel gene encoding a human homologue of yeast ubiquitin-conjugating enzymes which are critical for regulating the cell cycle.

From a human fetal-brain cDNA library we isolated a novel gene sharing significant homology with two yeast genes, UBC9 and hus5, which encode ubiquitin-conjugating enzyme 9 (UBC9). In yeast this protein is critical for normal mitosis, and seems to be closely involved in progression of G2 to M phase of the cell cycle. The human UBC9 (h-UBC9) cDNA, (gene symbol UBE2I), contained an open reading frame of 474 nucleotides encoding 158 amino acids. Its predicted peptide showed respectively 56% and 66% identity (75% and 82% similarity) with the products of UBC9 and hus5. Northern-blot analysis revealed expression of three transcripts, 6.4 kb, 3.3 kb, and 1.35 kb, in all human tissues examined. This gene, UBE2I, was mapped to chromosome band 16p13.3 by FISH.

Isolation and mapping of karyopherin α3 (KPNA3), a human gene that is highly homologous to genes encoding Xenopus importin, yeast SRP1 and human RCH1

From a human fetal-brain cDNA library, we isolated and characterized a novel gene (KPNA3) encoding a protein highly homologous to certain nuclear transport proteins of Xenopus and human. The complete cDNA clone, designated karyopherin alpha 3, contained an open reading frame of 1,563 nucleotides encoding 521 amino acids. The predicted amino acid sequence showed 48%, 45% and 48% identity with Xenopus importin, yeast SRP1 and human RCH1, respectively. The similarities among these proteins suggest that karyopherin alpha 3 may be involved in the nuclear transport system. Eight repeats of the arm motif were well conserved among these proteins. The N-terminal region of the predicted karyopherin alpha 3 product was highly basic and the C-terminal region was strongly acidic. A 4.3-kb transcript was expressed in all adult human tissues examined by Northern blotting. The cDNA clone was assigned to chromosome band 13q14.3 by fluorescence in situ hybridization.

Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily

A full-length cDNA homologous to RAB7, a member of the RAB-related GTP-binding protein subfamily, was isolated from a human placenta cDNA library. This cDNA, designated RAB7L1, has an open reading frame of 609 nucleotides encoding 203 amino acids. Northern analysis showed that the mRNA is ubiquitously expressed in human tissues, although signal intensities were different among the various organs examined. This gene was located on chromosome band 1q32 by fluorescence in situ hybridization.

Molecular cloning, characterization, and chromosomal mapping of a novel human gene (GTF3A) that is highly homologous to Xenopus transcription factor IIIA

We have isolated a novel human cDNA that is highly related to Xenopus transcription factor IIIA (TFIIIA). This clone contains an open reading frame of 1,269 nucleotides encoding 423 amino acids, including nine repeats of the Cys2His2-type of zinc-finger domain. A comparison of its sequence with Xenopus TFIIIA revealed 63% identity in nucleic acids and 58% identity in amino acids over a large portion of the gene and predicted peptide, indicating that the human homologue is likely to function as a transcription factor. The zinc-finger domains of the predicted protein also showed homology with those of human genes such as WT1, transcriptional repressor YY1, and MYC-associated zinc-finger protein (MAZ). Northern analysis showed expression in various tissues examined. The human TFIIIA gene (GTF3A) was localized to chromosome band 13q12.3-->q13.1 by fluorescent in situ hybridization (FISH).

Cloning, expression and chromosomal mapping of a novel cyclophilin-related gene (PPIL1) from human fetal brain

We isolated a human cDNA clone encoding a novel protein homologous to cyclophilins, specific cellular targets of cyclosporin A, which are conserved in species ranging from human to prokaryotes. This cDNA, designated hCyPX, contained an open reading frame of 498 nucleotides encoding 166 amino acids. Computer analysis indicated that its predicted amino acid sequence had 41.6%, 40.4%, and 39.2% homology to those of human, bovine, and Drosophila cyclophilins, respectively. Northern blot analysis indicated ubiquitous expression in adult human tissues, but most abundant expression in heart. Fluorescence in situ hybridization to human metaphase chromosomes localized this gene (PPIL1, peptidylprolyl isomerase [cyclophilin]-like 1) to chromosome bands 2p23.3-->p23.1.

Cloning, expression, and mapping of CKAPI, which encodes a putative cytoskeleton-associated protein containing a CAP-GLY domain.

From a human fetal-brain cDNA library we isolated a novel cDNA clone encoding a protein containing a CAP-GLY domain that is highly conserved among several cytoskeleton-associated proteins. The CAP-GLY domain is thought to be essential for their association with microtubules. The cDNA, designated CKAPI (for cytoskeleton-associated protein I, glycine motif) contained an open reading frame of 579 nucleotides encoding 193 amino acids. Northern-blot analysis revealed expression of three transcripts, 1.0, 3.4, and 4.6 kb in size, in all tissues examined. The 1.0-kb transcript was significantly higher in brain and heart than in other tissues. This gene was mapped by FISH to chromosome bands 19q13.11-->q13.12.

Cloning, expression pattern and mapping to 12p13.2→p13.1 of CLAPS3, a gene encoding a novel clathrin-adaptor small chain

From a human fetal-brain cDNA library we isolated a novel gene encoding a peptide homologous to clathrin-adaptor small chains in rat, mouse, and yeast. The cDNA, designated CLAPS3 (clathrin-associated/assembly/adaptor protein, small 3, 22 kDa), contained an open reading frame of 579 nucleotides encoding 193 amino acids. Northern-blot analysis revealed expression of a 1.35-kb transcript in all human tissues examined. This gene was mapped to chromosome bands 12p13.2 --> p13.1 by FISH.