Biomedical subjects

Yumin Mao

Publications and source records attributed to Yumin Mao.

At least 91 records · Page 5Linked to original sources

PubMed2003

Cloning and sequence analysis of the human cDNA encoding the synaptoporin (delta), a highly conservative synaptic vesicle protein.

Synaptoporin is a membrane protein of synaptic vesicles, which belongs to the synaptophysin family. It was first isolated from rat brain. Here we report the cloning and characterization of the human cDNA that encodes the human homologue of synaptoporin. It has two splicing variants, which is in accordance with its ortholog in chicken. Its deduced amino acid sequence displays 97% and 81% identity with the synaptoporin of rat and chicken, respectively. This gene was mapped to the chromosome 3p14.3 by matching against the Human Genome Sequence Database. 16-tissue RT-PCR analysis shows that human synaptoporin is specifically expressed in the brain.

Amino Acid Sequence↗

PubMed2003

Characterization of the tissue-specific expression of the s100P gene which encodes an EF-hand Ca2+-binding protein.

S100 proteins are a calcium-binding protein family containing two EF-hand domains exclusively expressed in vertebrates and play roles in many cellular activities. Human S100P gene was first cloned as a 439 bp cDNA in placenta and it was found to be associated with human prostate cancer. Here we describe the cloning of the 1297 bp full-length cDNA, and the characterization of the tissue-specific expression of the human S100P gene. It is abundantly expressed in many tissues including placenta by Northern blot and RT-PCR analysis, unlike the expression pattern of other S100 family genes.

Amino Acid Sequence↗

PubMed2003

Cloning and characterization of the human IFT20 gene.

Intraflagellar transport (IFT), in which molecular motors and IFT particle proteins participate, is very important in assembling and maintaining many cilia/flagella, such as the motile cilia that drive the swimming of cells and embryos, the nodal cilia that generate left-right asymmetry in vertebrate embryos, and the sensory cilia that detect sensory stimuli in some animals. Here we report the molecular cloning and characterization of a novel human cDNA that is 1060 base pair in length, encoding a putative protein of 158 amino acid residues which shares high homology to Mus musculus intraflagellar transport protein mIFT20 (Accession number AAL99202, identity 82.3%, similarity 82.9%) at protein level. Bioinformatics analysis revealed that the gene is composed of 6 exons and is located on human chromosome 17p 11.1. RT-PCR showed that this gene is expressed in human brain, lung, kidney and pancreas, and lower expression were also detected in human placenta, liver, thymus, prostate and testis.

Amino Acid Sequence↗

PubMed2003

Characterization of a novel splicing variant of KLHL5, a member of the kelch protein family.

The kelch-repeat protein family is a recently found new kind of actin-binding protein. It is characterized by tandemly arranged motifs of about 50 amino acids. Previous study showed that most members of the kelch-repeat family were cytoskeletal proteins implicated in various cellular processes, such as actin cytoskeleton interaction, cytoplasmic sequestration of transcription factors and cell morphology. And some of the family members play important roles in tissue development, such as human ENC-1, NRP/B, etc. Another characteristic of the kelch family is that most members have another conserved BTB domain at the extreme amino terminus. The BTB domain is also found at the N-terminus of 5-10% of zinc-finger transcription factor types and is a conserved protein-protein interaction motif. During the large-scale sequencing analysis of a human fetal brain cDNA library we found a novel kelch-like protein gene 5, KLHL5, KLHL5 has high identity with Drosophila kelch protein and many other family members. Here we report a novel splicing variants of KLHL5, named KLHL5b and the expression pattern of KLHL5b in many tissues.

Alternative Splicing↗

PubMed2003

Molecular cloning and characterization of a novel human putative transmembrane protein homologous to mouse sideroflexin associated with sideroblastic anemia.

Sideroflexin1 (Sfxn1), the prototype of a novel family of evolutionarily conserved proteins present in eukaryotes, has been found mutated in mice with siderocytic anemia. It is speculated that this protein facilitates the transport of a component required for iron utilization into mitochondrial. During the large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a cDNA encoding a novel sideroflexin protein (SFXN4), which showed 59% identity and 71% similarity to mouse sideroflexin4. According to the search of the human genome database, SFXN4 gene is mapped to chromosome 10q25-26 and spans more than 24.7kb of the genomic DNA. It is 1428 base pair in length and the putative protein contains 305 amino acids with a conserved predicted five-transmembrane-domains structure. RT-PCR result shows that the SFXN4 gene is expressed in many tissues.

Amino Acid Sequence↗

PubMed2003

Cloning and characterization of human synaptotagmin 10 gene.

Synaptotagmin (Syt) is a membrane protein family of secretory vesicles, abundant in neural and some endocrine cells. All the members of this family contain one transmembrane region and two conserved C2 domains. Here we reported a new human Syt 10 gene isolated when screening a human fetal brain cDNA library. This cDNA clone is 3287 bp and contains an open reading frame from 299 to 1870 encoding a putative protein of 523 amino acids. It shares 94.6 and 94.8% homology to rat Syt 10 and mouse Syt 10 at protein level, respectively. RT-PCR result showed that it is expressed only in pancreas, lung and kidney.

Amino Acid Sequence↗

PubMed2003

Cloning and characterization of a novel splice variant of the brain-specific protein densin-180.

Densin-180 is a brain-specific synaptic protein of the o-sialoglycoprotein family. It functions in specific adhesion between presynaptic and postsynaptic membranes at glutamatergic synapses. We have cloned a novel splice variant of densin-180 from a fetal brain cDNA library and termed it LRRC7. It is located on 1p31 and consists of 8 exons. It encodes a putative protein of 216 amino acids which contains a nuclear localization signal and four leucine-rich repeats (LRRs). LRRs are 20-29 residue sequence motifs present in a number of proteins with diverse functions. Expression analysis of LRRC7 shows it is expressed ubiquitously while its splice variant densin-180 is brain-specific.

Alternative Splicing↗

PubMed2003

Identification and expression analysis of a novel splice variant of human Sprouty1 gene.

Sprouty (SPRY) was first identified in a genetic screen in Drosophila to be an antagonist of fibroblast growth factor (FGF) and epidermal growth factor (EGF) signaling, seemingly by inhibiting the Ras/MAP kinase pathway. During large scale DNA sequencing of the human fetal brain cDNA library, we cloned a novel splice variant of human Sprouty1 gene, and termed it human Sprouty1b (SPRY1b). It has the same deduced protein as Sprouty1a, which has been reported. And like other members of Sprouty family, SPRY1b deduced protein also has a C-terminal cysteine-rich region. According to the search against human genome database, SPRY1b was mapped to 4q25-28. Expression analysis of SPRY1a and SPRY1b shows that they are hardly expressed in adult human, but have different expression patterns in fetus, which confirmed that SPRY1 is an important gene during fetal development.

Adaptor Proteins, Signal Transducing↗

PubMed2003

A novel splice variant of human gene GDPD1 is mainly expressed in human ovary and small intestine.

Glycerophosphodiester phosphodiesterase (GDPD) is a glycerol metabolizing enzyme that has been previously identified in Escherichia coli, Haemophilus influenzae, Bacillus subtilis and Borrelia hermsii. It has been also reported that there is putative protein containing GDPD domain in Mus musculus, but not in Homo sapiens. SMART analysis showed that our predicted protein and three others of the same gene also comprise this domain. Because the gene has not been named, we termed it GDPD1 and accordingly termed our splice variant GDPD1_v1 after acquiring the agreement of HUGO. RT-PCR experiment revealed that our splice variant of the gene is mainly expressed in human ovary and small intestine, basically conforming to the result of serial analysis of gene expression.

Alternative Splicing↗

PubMed2002

cDNA cloning and expression analysis of a novel human F-box only protein.

F-box proteins are an expanding family of eukaryotic proteins that are characterized by an approximately 40 amino acid motif. Some F-box proteins are critical for the controlled degradation of cellular regulatory proteins. During a large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a cDNA clone that encodes a novel F-box protein. It showed a 90.0% identity with the previously isolated mouse F-box protein16 at the amino acid level. Northern blot analysis showed no detectable expression, while reverse transcription-polymerase chain reaction analysis indicated that FBXO16 was expressed in the heart, spleen, and colon. By mapping, we localized the FBXO16 gene to the human chromosome 8p12. The FBXO16 gene consisted of 9 exons that spanned 67,816 bp of human genomic DNA.

Amino Acid Sequence↗

PubMed2002

Discovery and analysis of hepatocellular carcinoma genes using cDNA microarrays.

PURPOSE: Microarray analysis on a genomic scale was used to profile changes in gene expression accompanying hepatocellular carcinoma. METHODS: Gene expression profiles of liver tissues from twelve hepatocellular carcinoma samples relative to the gene expression profile of the normal liver tissue were analyzed using 4096 chips and 12800 chips. The results of microarray experiments were verified by the Northern blot technique. RESULTS: A group of 1,820 genes with altered expression were identified in more than 50% of the patients examined. This highly concordant expression profile included human genes encoding proteins involved in the function of peroxisomes, serum control, polycyclic aromatic hydrocarbon carcinogenesis, cell growth and differentiation, metastasis, the function of the immune system, apoptosis, and remodeling of the cytoskeleton. CONCLUSIONS: The newly identified genes afford a quantitative view of the changes that accompany liver cancer at the genomic level, enable deeper insights into the molecular basis of disease, and provide an extensive list of potential early-onset molecular markers for improved diagnosis.

Adult↗

PubMed2002

Occurrence of leu+ revertants under starvation cultures in Escherichia coli is growth-dependent.

BACKGROUND: Many investigations have reported that advantageous mutations occurred more frequently under selective conditions than those under non-selective conditions. This phenomenon is referred to as adaptive mutation. Their characteristics are that adaptive mutations are directed and growth-independent. The idea of directed adaptive mutation had been objected by some reports, however, the idea of growth-independent adaptive mutation has been held till today. RESULTS: In this paper, we have observed that under leucine starvation conditions, leu+ revertants accumulated as a function of time; leu- to leu+ reverse mutation rates and frequencies were higher than those under non starvation conditions; and no divided cells could be monitored by the penicillin method. These results were similar to the time-dependent manner of adaptive mutation from previous reports. However, leucine concentration determinate experiments revealed that certain traces of leucine, which leaked from the E. coli cells, was almost always present in the culture. More numbers of leu+ revertants appeared when the similar cultures were dropped in small areas on the selective plates than when spread on the whole selective plates. These results have shown that mutations under leucine starving conditions are growth-dependent. Fluctuation analysis of leu+ revertants indicated that leu-leu+ mutation occurred spontaneously and randomly. In addition, the spectra of leuB gene in the revertants proved that mutations under selective conditions were not specific or directed. CONCLUSIONS: The above investigations led to the conclusion (1) that the occurrence of leu+ mutations under starvation conditions was growth-dependent. The occurrence mutations was also similar to that under non-starvation conditions (2). Under starvation conditions the mutation rates were higher, and was not constant during the long process.

3-Isopropylmalate Dehydrogenase↗

PubMed2002

Cloning, characterization, and expression of calcyphosine 2, a novel human gene encoding an EF-hand Ca(2+)-binding protein.

Calcyphosine is a calcium-binding protein containing four EF-hand domains, initially identified as thyroid protein p24. It was first cloned and its counterparts in rabbit, human, and mouse, crayfish and lobster of invertebrate were also cloned. Here we describe the cloning and characterization of a novel human calcyphosine gene. The 3829-bp cDNA encodes a EF-hand Ca(2+)-binding protein homologous to the dog calcyphosine. It also contains two EF-hand Ca(2+)-binding motif. It is abundantly expressed in many tissues including by RT-PCR analysis and believed to play important role in calcium signaling. It was mapped to human genome 12q15.

Amino Acid Sequence↗

PubMed2002

Cloning, expression and characterisation of a human Nudix hydrolase specific for adenosine 5'-diphosphoribose (ADP-ribose).

The human NUDT9 gene has been mapped to 4q22 and shown to give rise to two alternatively spliced mRNAs, NUDT9alpha and NUDT9beta, that encode a member of the Nudix hydrolase family. Both transcripts were readily detected in heart and skeletal muscle and also in liver, kidney and pancreas. NUDT9alpha protein was expressed in Escherichia coli and shown specifically to hydrolyse ADP-ribose and IDP-ribose to the corresponding nucleoside 5'-monophosphates and ribose 5-phosphate. No other nucleotide substrates were hydrolysed significantly. NUDT9alpha was inhibited by fluoride and by N-acetyl-p-benzoquinoneimine and had K(m) and kcat values of 180 microM and 8 s(-1) respectively with ADP-ribose as substrate. The full-length 39.1 kDa NUDT9alpha has a potential mitochondrial leader sequence, which would give rise to a mature 34.2 kDa mitochondrial protein. Apart from the high K(m) value, the properties of NUDT9alpha are close to those of the known mammalian 40 kDa cytoplasmic ADPRibase-1 and 35 kDa mitochondrial ADPRibase-m. However, any relationship between the NUDT9 species and the previously reported ADPRibases remains to be established.

Adenosine Diphosphate Ribose↗

PubMed2002

Cloning, chromosome localization and features of a novel human gene, MATH2.

We report cloning and some features of a novel human gene, MATH2, which encodes a protein of 337 amino acid residues with a basic helix loop helix domain and exhibits 98% similarity to mouse Math2. Results of Northern blot analysis revealed two transcripts of the MATH2 gene of 1.7 kb and 2.4 kb in human brain. We localized MATH2 to chromosome 7 at 7p14-15 by matching with the Human Genome Sequence Database. Human MATH2 and mouse Math2 may have the same functions in the nervous system.

Amino Acid Sequence↗

PubMed2002

Molecular cloning and characterization of a novel human cAMP response element-binding ( CREB) gene ( CREB4).

Cyclic adenosine monophosphate (cAMP) response element-binding (CREB) proteins are a family of mammalian transcription activators. We identified a novel human CREB gene ( CREB4) that was 1592 bp long and encoded a protein of 395 amino acid residues. The protein shared high homology to mouse CREB3 (identity 62%, similarity 72%). The expression pattern of the human CREB4 gene showed transcripts in prostate, brain, pancreas, skeletal muscle, small intestine, testis, leukocyte, and thymus, whereas in heart, lung, liver, kidney, placenta, spleen, ovary, and colon, specific bands of the transcript could not be detected. The CREB4 gene consisted of ten exons and nine introns and was mapped to chromosome 1q21.3 by means of a bioinformatics analysis.

Amino Acid Sequence↗

PubMed2002

A novel splice variant of the cell adhesion molecule contactin 4 ( CNTN4) is mainly expressed in human brain.

Axon-associated cell adhesion molecules (AxCAMs) of the immunoglobulin superfamily play important roles in the formation, maintenance, and plasticity of functional neuronal networks. Contactin4 ( CNTN4, BIG-2) is a member of the TAG-1/F3 subgroup of AxCAMs. We have cloned a novel splice variant of CNTN4, and term it CNTN4A. The complete nucleotide sequence of CNTN4 is also obtained by combining the insert sequences of two clones, which were isolated when screening the human fetal brain cDNA library with CNTN4A as a probe. CNTN4A protein has an N-terminal cleavable signal peptide, two FNIII-like domains, and a glycosyl phosphatidylinositol-anchoring domain. According to the search of the human genome database, CNTN4 was mapped to 3p25-26, a region very close to the breakpoints of the 3p syndrome. Expression analysis of CNTN4A shows that CNTN4A is mainly expressed in brain.

Alternative Splicing↗

PubMed2002

Molecular cloning and characterization of a novel human Rab ( Rab2B) gene.

Rab proteins are small-molecular-weight guanosine triphosphatases (GTPases) that control vesicular traffic in eukaryotic cells. The small GTPase Rab2 is a resident of pre-Golgi intermediates and is required for protein transport from the endoplasmic reticulum to the Golgi complex. We identified a novel human Rab (Rab2B) gene that was 2312 bp in length and encoded a protein of 216 amino acid residues. The protein shared high homology with mouse Rab2 (identity 83%, similarity 91%). The expression pattern of the human Rab2B gene showed that there is a transcript in kidney, prostate, lung, liver, thymus, colon, pancreas, and skeletal muscle, and low levels in placenta, whereas specific bands of the transcript could not be detected in heart, brain, spleen, testis, ovary, small intestine, and leukocyte. Overexpression has been observed in colon adenocarcinoma CX-1. The Rab2B gene consists of nine exons and eight introns and is mapped to chromosome 14q11.1-14q11.2 by bioinformatics analysis.

Aged↗