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S S Li

Publications and source records attributed to S S Li.

At least 37 records · Page 2Linked to original sources
PubMed1998

Characterization of mouse ubiquitin-like SMT3A and SMT3B cDNAs and gene/pseudogenes.

Mouse SMT3A and SMT3B cDNAs encoding ubiquitin-like proteins of 110 and 95 amino acids, respectively, were isolated and sequenced. The sequence of the first 92 amino acids (ending with the conserved Gly-Gly) of mouse SMT3A exhibited two differences at amino acid no. 38 and 76 in comparison with that of human SMT3A. The C-terminal 18 amino acid sequence of mouse SMT3A was completely different from the C-terminal 11 amino acid sequence of human SMT3A. Mouse and human SMT3B were identical for a sequence of 95 amino acids. Mouse SMT3A genomic DNAs were amplified by polymerase-chain-reaction and sequenced. The nucleotide sequence of a PCR-amplified SMT3A genomic DNA fragment was found to be identical to that of SMT3A cDNA, indicating the absence of intron(s) in its protein coding region. Another genomic DNA fragment of 1,531 nucleotides, containing 7% differences from that of cDNA, is unable to encode a functional protein, and thus, it is a SMT3A processed pseudogene. Three mouse SMT3B processed pseudogenes were cloned and sequenced. The genuine mouse SMT3B gene has not yet been isolated. Mouse SMT3A transcript of 1.8 kb was predominantly expressed in most tissues, while SMT3B transcript of 1.0 kb was abundantly present in all tissues analyzed. A family of ubiquitin-like proteins was recently discovered. One distinguishing feature of ubiquitin and ubiquitin-like proteins is the capacity to conjugate with other proteins post-translationally. The ubiquitin-like proteins are cleaved endoproteolytically after a diglycine sequence, corresponding to the C-terminal Gly75-Gly76 of ubiquitin. The cleavage activates the molecule for conjugation. The yeast SMT3 gene was originally identified as a suppressor of mutations in MIF2 gene, which encodes an essential protein binding to the A+T-rich CDEII region of centromere DNA (1). Studies using temperature-sensitive mutants showed that the loss of yeast Mif2 protein function results in chromosome missegregation, mitotic delay, and aberrant microtubule morphologies (2). The yeast Mif2 protein shares at least two regions of similarity with mammalian centromere protein CENP-C, an integral component of active kinetochores (3, 4). Human SMT3A cDNA was identified from the genome sequencing project of chromosome 21 (5). We have cloned human SMT3B (formerly designated as HSMT3) cDNA (6). Human SMT3C protein was independently isolated by several groups and denoted as SUMO-1 (7), GMP1 (8), PICI (9), UBL1 (10), sentrin (11). SUMO-1/GMP1 was found to be covalently linked to the Ran GTPase-activating protein RanGAP1, and attachment of SUMO-1 targets the otherwise cytosolic RanGAP1 to the nuclear pore complex. The modified form of RanGAP1 also appeared to associate with the mitotic spindle apparatus during mitosis (7, 8). PIC1 was shown to interact with the PML component of nuclear multiprotein complex that is disrupted in acute promyelocytic leukemia (9). UBL1 was found to associate with human RAD51/RAD52 proteins involved in DNA recombination and DNA double-strand break repair (10). Sentrin was shown to interact with Fas/APO-1 or the TNF receptor 1 death domain, and the overexpression of sentrin provided protection against both anti-Fas/APO-1 and TNF-induced cell death (11). Here we report the characterization of mouse SMT3A and SMT3B cDNAs, gene/pseudogenes, and mRNA expression.

Amino Acid Sequence↗
PubMed1998

Genomic organization and chromosome localization to band 19p13.3 of the human AES gene: gene product exhibits strong similarity to the N-terminal domain of Drosophila enhancer of Split Groucho protein.

The human Amino Enhancer of Split (AES) gene encodes a protein of 197 amino acids exhibiting strong similarity to the N-terminal domain of Drosophila Enhancer of Split Groucho (ESG) protein. The nucleotide sequence of approximately 12 kb from the human AES gene was determined, and its protein-encoding sequence was shown to be interrupted by six introns. The human AES gene was further localized by fluorescence in situ hybridization to chromosome band 19p13.3 near the transcription factor 3 (TCF3) gene.

Amino Acid Sequence↗
PubMed1998

Trends in food label use associated with new nutrition labeling regulations.

OBJECTIVES: This study compared use of food labels before and after implementation of new Food and Drug Administration regulations in 1994. METHODS: Data were obtained by random-digit-dial surveys of Washington State residents in 1993 (n = 1001) and 1996 (n = 1450). RESULTS: After implementation of the new regulations, usual label use increased significantly, by 8.5 percentage points in women and 11.3 percentage points in men. More respondents looked for information on fat content and fewer failed to use labels because they "take too much time" or "are too hard to understand. CONCLUSIONS: Use of food labels and satisfaction with their content have increased, but 70% of adults still want labels to be easier to understand.

Adolescent↗
PubMed1998

Teleconferencing in endoscopic surgery.

The traditional methods of information dissemination by publication in journals and the classical model of instruction by apprenticeship have not been able to keep pace with the rapid advances in the fields of therapeutic endoscopy and laparascopic surgery. The advances in communications technology have made it possible to transmit images of operative procedures over long distances. In recent years, teaching workshops where procedures are demonstrated in a real-time fashion have become very popular. This article discusses the logistics, limitations, and problems that may be encountered in conducting such workshops.

Journal Article↗
PubMed1998

Molecular characterization of germline mutations in neurofibromatosis 2 in two families.

Neurofibromatosis 2 (NF2) is an autosomal dominant disorder that predisposes patients to central nervous system tumors. It is caused by mutations in the NF2 tumor suppressor gene, which is located on chromosome 22q12. We studied 2 multigenerational NF2 families (three members of family 1 and the proband of the family) by gene mutation analysis and clinical assessment. One member of family 1 had a 169 C-->T point mutation at codon 57 of exon 2 and had a severe phenotype. His father had a silent 1113 C-->T point mutation at codon 371 of exon 11 and had a normal phenotype. The proband of family 2 had a deletion at nucleotide 720 G (codon 240) of exon 8. This led to a frameshift and termination at codon 250, and a severe NF2 phenotype. Our results indicate that clinical abnormalities can be present in carriers. Nonsense and frameshift mutations in the NF2 tumor suppressor gene are associated with phenotypes. The clinical abnormalities can develop at a young age.

Adult↗
PubMed1997

Cloning and developmental expression of Xenopus cDNAs encoding the Enhancer of split groucho and related proteins.

The two full-length cDNAs encoding ESG1 (Enhancer of split groucho) and related AES (Amino Enhancer of split) proteins of 767 and 197 amino acids, respectively, were cloned and sequenced from the African frog Xenopus laevis. The amino acid sequence of Xenopus ESG1 protein had 61% identity to the full-length Drosophila groucho. Xenopus AES protein exhibited 91%, 58% and 48% identity to the mouse AES, amino-terminal regions of Xenopus ESG1 and Drosophila groucho, respectively. Northern blot analysis showed that widespread RNA expression of ESG1 of 2.8 kb, ESG2 of 3.6 kb and AES of 2.2 kb transcripts were seen in adult tissues, whereas ESG1 and AES transcripts of 2.8 kb and 2.2 kb, respectively, were ubiquitously expressed in the developing embryos. The overall structural relationships of ESG and AES proteins among human, mouse, rat, Xenopus and Drosophila were analysed.

Amino Acid Sequence↗
PubMed1997

Identification and characterization of the SMT3 cDNA and gene from nematode Caenorhabditis elegans.

SMT3 gene from nematode, Caenorhabditis elegans, was identified and sequenced. The nematode SMT3 gene codes for a homolog to the yeast SMT3, suppressor of MIF2 mutation in a centromere protein gene. Further, nematode SMT3 cDNA was amplified by polymerase chain reaction from a cDNA library and its nucleotide sequence determined. A comparison of the SMT3 genomic and cDNA sequences established that the protein-encoding sequence is interrupted by two introns of 56 and 50 bp at codon Nos. 22-23 and 56, respectively. The sequence of 91 amino acids deduced from the nematode SMT3 nucleotide sequence exhibited 42 and 47% identity to the yeast and human SMT3 protein sequences, respectively. The evolutionary relationships of SMT3 proteins from human, nematode, Arabidopsis, rice, and yeast were analyzed.

Amino Acid Sequence↗
PubMed1997

Identification of LDH-ras p21 protein complex and expression of these genes in human ovarian cancer.

Normal ovarian and ovarian cancer tissues from 35 patients were tested for LDH-A-ras protein complex formation, as well as for the expression of ras and LDH-A genes. By immunodetection of the immunoprecipitates, LDH-A-ras protein complexes are present in the homogenates of human ovarian tissues (benign and malignant). Two bands of 21 and 36 kDa were demonstrated in affinity-purified LDH active fractions by Western blot analysis, and these two proteins were proved to be ras p21 and LDH-A by immunodetection. By Northern blot analysis, elevated levels of c-Ki-ras and LDH-A mRNA transcripts were noted in 49% (17/35) and 40% (14/35) of ovarian cancers, respectively. Concurrent high expression of both genes was demonstrated in 11 cases (31%). Tyrosylphosphorylation of LDH-A was demonstrated in normal and malignant ovarian tissues, and the extent of phosphorylation was correlated with the stage of ovarian cancer. The concurrent elevated expression of ras and LDH-A in the same ovarian tissue may imply that the increased synthesis of LDH-A is due to increased or amplified signaling of the ras-cascade pathway. The possible biochemical role of the tyrosylphosphorylated LDH-A complexed with ras p21 in cell transformation and progression of human ovarian cancer is worthy of further investigation.

Female↗
PubMed1997

cDNA cloning and genomic organization of enhancer of split groucho gene from nematode Caenorhabditis elegans.

This first genomic Enhancer of split groucho (ESG) gene and its full length complementary DNA (cDNA) from nematode C. elegans were cloned and sequenced via homology with the corresponding Drosophila groucho cDNA. The cDNA of 2.1-Kb encodes a protein of 612 amino acids, and the nematode ESG protein is the smallest and most different in structure compared to all ESG related proteins. The gene isolated is 4,246-bp in size, including 1,219-bp promoter region. A putative TATA-box at position -1166, two consensus sequence of ACTGG, characteristic of leader binding protein-1 (LBP-1) binding motifs at position -563 and -211 and nine CAAT boxes were found in the promoter region of ESG gene. The protein-coding sequence is interrupted by five introns. The length of introns 1 to 5 is 52, 252, 87, 53 and 518 bp, respectively. The overall structural relationships of the ESG-related proteins among human, mouse, rat, Xenopus, Drosophila and nematode were also analyzed.

Amino Acid Sequence↗
PubMed1997

The cDNA cloning and molecular evolution of reptile and pigeon lactate dehydrogenase isozymes.

The cDNAs encoding lactate dehydrogenase isozymes LDH-A (muscle) and LDH-B (heart) from alligator and turtle and LDH-A, LDH-B, and LDH-C (testis) from pigeon were cloned and sequenced. The evolutionary relationships among vertebrate LDH isozymes were analyzed. Contrary to the traditional belief that the turtle lineage branched off before the divergence between the lizard/alligator and bird lineages, the turtle lineage was found to be clustered with either the alligator lineage or the alligator-bird clade, while the lizard lineage was found to have branched off before the divergence between the alligator/turtle and bird lineages. The pigeon testicular LDH-C isozyme was evidently duplicated from LDH-B (heart), so it is not orthologous to the mammalian testicular LDH-C isozymes.

Alligators and Crocodiles↗
PubMed1996

Cloning and expression of human homolog HSMT3 to yeast SMT3 suppressor of MIF2 mutations in a centromere protein gene.

A human HSMT3 cDNA encoding a homolog of the yeast SMT3, a suppressor of MIF2 mutations in a centromere protein gene, was identified and sequenced. The sequence of 95 amino acids deduced from the human HSMT3 cDNA exhibited 51.1% identity and 69.6% similarity to the yeast Smt3p sequence. The HSMT3 transcripts of 1.35Kb were found to be abundantly expressed in various human tissues.

Amino Acid Sequence↗
PubMed1996

Human prostatic acid phosphatase and prostate specific antigen: protein structure, gene organization, and expression in neoplastic and benign tissues.

Human prostatic acid phosphatase (ACPP) and prostate specific antigen (PSA) have been used as diagnostic and prognostic markers of prostate cancer. The structure of ACPP and PSA genes and their encoded proteins are described. The expression of both genes was shown to be elevated significantly in neoplastic tissue when compared to benign prostatic hyperplasia. The prospect of developing new molecular DNA/RNA markers to diagnose prostate cancer is discussed.

Acid Phosphatase↗
PubMed1995

The lactate dehydrogenase gene from nematode Caenorhabditis elegans contains only two of six introns conserved in the protein-encoding sequence of LDH genes from bird and mammals.

The protein-encoding region of L-lactate dehydrogenase (LDH) gene from nematode, Caenorhabditis elegans, was amplified by polymerase-chain-reaction from total genomic DNA and its nucleotide sequence determined. A comparison of this genomic sequence with the published sequence of nematode LDH cDNA reveals the presence of two introns of 57 and 47 nucleotides at codon no. 82 and 279-280, respectively. The positions of the two introns present in this invertebrate LDH gene correspond to the second and sixth introns of vertebrate LDH genes. The protein-coding sequence of human LDH-A (muscle), LDH-B (heart) and LDH-C (testis), mouse LDH-A, and duck LDH-B genes has previously been shown to be interrupted by six introns at the homologous positions.

Amino Acid Sequence↗
PubMed1994

The nucleotide and deduced amino-acid sequences of a cDNA encoding lactate dehydrogenase from Caenorhabditis elegans: the evolutionary relationships of lactate dehydrogenases from mammals, birds, amphibian, fish, nematode, plants, bacteria, mycoplasma, and plasmodium.

The nucleotide and deduced amino-acid sequences of a cDNA encoding L-lactate dehydrogenase (LDH) from nematode, Caenorhabditis elegans, were reported. This first invertebrate LDH sequence of 333 amino acids, including the initiation methionine, exhibits 63% identity with that of the most primitive vertebrate lamprey. The evolutionary relationships among 36 LDH isozymes from mammals, birds, amphibian, fish, nematode, plants, bacteria, mycoplasma and plasmodium were analyzed. The invertebrate nematode LDH is evolutionarily positioned between plant LDH and mammalian testicular LDH-C isozymes. The mammalian LDH-C isozyme appears to have arisen after the invertebrate LDH, but prior to the divergence of vertebrate LDH-A (muscle) and LDH-B (heart) isozymes as described previously.

Amino Acid Sequence↗
PubMed1994

Evolutionary relationships of lactate dehydrogenases (LDHs) from mammals, birds, an amphibian, fish, barley, and bacteria: LDH cDNA sequences from Xenopus, pig, and rat.

The nucleotide sequences of the cDNAs encoding LDH (EC 1.1.1.27) subunits LDH-A (muscle), LDH-B (liver), and LDH-C (oocyte) from Xenopus laevis, LDH-A (muscle) and LDH-B (heart) from pig, and LDH-B (heart) and LDH-C (testis) from rat were determined. These seven newly deduced amino acid sequences and 22 other published LDH sequences, and three unpublished fish LDH-A sequences kindly provided by G. N. Somero and D. A. Powers, were used to construct the most parsimonious phylogenetic tree of these 32 LDH subunits from mammals, birds, an amphibian, fish, barley, and bacteria. There have been at least six LDH gene duplications among the vertebrates. The Xenopus LDH-A, LDH-B, and LDH-C subunits are most closely related to each other and then are more closely related to vertebrate LDH-B than LDH-A. Three fish LDH-As, as well as a single LDH of lamprey, also seem to be more related to vertebrate LDH-B than to land vertebrate LDH-A. The mammalian LDH-C (testis) subunit appears to have diverged very early, prior to the divergence of vertebrate LDH-A and LDH-B subunits, as reported previously.

Amino Acid Sequence↗
PubMed1994

Population screening of lactate dehydrogenase deficiencies in Fukuoka Prefecture in Japan and molecular characterization of three independent mutations in the lactate dehydrogenase-B(H) gene.

Screening for lactate dehydrogenase (LDH) subunit deficiencies was performed on 2880 blood samples from healthy individuals in the Fukuoka Prefecture in Japan by means of electrophoresis. The frequencies of heterozygotes with either LDH-A or LDH-B deficiency were found to be 0.104% at each locus. These estimated frequencies of either LDH-A or LDH-B deficiencies were slightly lower than, but not significantly different from, those found previously in Shizuoka Prefecture. The genetic mutations in individuals heterozygous for LDH-B deficiency were analyzed by the polymerase chain reaction and DNA conformation polymorphism. Abnormal migration patterns were observed in individuals heterozygous for LDH-B deficiency. Subsequent sequence determination of the mutant alleles revealed three novel mutations: an eight-base duplication in exon 3, a four-base duplication in exon 4, and a one-base deletion in exon 7 of the LDH-B gene. These three mutations result in frame-shift translation and premature termination. In addition, the mutations resulting in the duplication of eight or four nucleotides appear to cause a decrease in the levels of LDH-B mRNA.

Amino Acid Sequence↗
PubMed1994

Endoscopic Nd:YAG laser therapy in patients with early superficial carcinoma of the esophagus and the gastric cardia.

A group of 33 patients, 27 with early superficial esophageal cancer and six with early superficial carcinoma of the gastric cardia, were treated with endoscopic neodymium:yttrium aluminum garnet (Nd:YAG) laser from April 1989 to March 1993. Of the 33 patients, in 32 (97%) the disappearance of the cancer cells was noted. They were treated 1-6 times (average 2.6) with laser irradiation. No serious complications, such as perforation, occurred in the series. Twenty-two patients were followed up for 24-55 months. A negative biopsy was recorded in 16 (72.7%) of the 22 patients; the other six (27.3%) cases were found to have recurrent early cancer during the follow-up period from the 36th to the 40th months, and were treated with supplementary endoscopic therapy or surgical resection. It is suggested that endoscopic Nd: YAG laser may be a safe and effective therapy for early carcinoma of the esophagus and the gastric cardia, when the risks of surgery are too high or the patient has refused surgical resection.

Adult↗