Two polymorphisms, apolipoprotein A5 (APOA5) -1131T>C and apolipoprotein C3 (APOC3) -482C>T, were examined in a healthy Chinese group. Analysis of covariance (ancova) showed that both -1131T>C and -48 Show more
Two polymorphisms, apolipoprotein A5 (APOA5) -1131T>C and apolipoprotein C3 (APOC3) -482C>T, were examined in a healthy Chinese group. Analysis of covariance (ancova) showed that both -1131T>C and -482C>T minor alleles were associated with triglyceride (TG)-raising effects (p < 0.001 and p = 0.012, respectively) after adjustment of sex, age, and body mass index (BMI). Moreover, -1131T>C minor alleles were also found to be associated with total cholesterol (TC)-raising effects (p = 0.045). However, the relationship between -482C>T minor alleles and TC-raising effects was not observed after adjustment of sex, age, and BMI. By contrast, significant inverse associations were noted between minor alleles (-1131T>C and -482C>T) and high-density lipoprotein cholesterol (HDL-C) concentrations (p = 0.021 and p = 0.021, respectively). Linear regression analysis showed that the effects of -1131T>C and -482C>T polymorphisms on TG and HDL-C (0.001 and 0.008; 0.041 and 0.005, respectively) are independent and additive and that -1131T>C can seriously affect the levels of TG (0.001 vs 0.008). The additive effect of the two polymorphisms was confirmed further by haplotype analysis. Our results strongly support that the two single nucleotide polymorphisms, -1131T>C in APOA5 and -482C>T in APOC3, are related to the levels of serum TG and HDL-C and those of other several lipids and lipoproteins in the Chinese population. Show less
A polysaccharide from the water extract of cultured Cordyceps militaris was isolated through ethanol precipitation, deproteination and gel-filtration chromatography. Their molecular weight was determi Show more
A polysaccharide from the water extract of cultured Cordyceps militaris was isolated through ethanol precipitation, deproteination and gel-filtration chromatography. Their molecular weight was determined using gel-filtration chromatography. The structure of polysaccharide CPS-1 was elucidated by sugar analysis, Smith degradation, IR and 13C-NMR spectroscopy. CPS-1 was shown to possess a significant antiinflammatory activity and suppressed the humoral immunity in mice but had no significant effects on the cellular immunity and the non-specific immunity. Show less
The transcriptomes of mouse type A spermatogonia (Spga), pachytene spermatocytes (Spcy), and round spermatids (Sptd) were determined by sequencing the respective SAGE (Serial Analysis of Gene Expressi Show more
The transcriptomes of mouse type A spermatogonia (Spga), pachytene spermatocytes (Spcy), and round spermatids (Sptd) were determined by sequencing the respective SAGE (Serial Analysis of Gene Expression) libraries. A total of 444,015 tags derived from one Spga, two Spcy, and one Sptd library were analyzed, and 34,619 different species of transcripts were identified, 5279 of which were novel. Results indicated the germ-cell transcriptome comprises of more than 30,000 transcripts. Virtual subtraction showed that cell-specific transcripts constitute 12-19.5% of the transcriptome. Components of the protein biosynthetic machinery are highly expressed in Spga. In Spcy transcription factors are abundantly expressed while transcripts encoding proteins involved in chromosome remodeling and testis-specific transcripts are prominent in Sptd. The databases generated by this work provide very useful resources for cellular localization of genes in silico. They are also extremely useful as sources for identification of splice variants of genes in germ cells. Show less
To investigate the expression of RDH10, an all-trans retinol dehydrogenase identified in the retinal pigment epithelium (RPE), in retinal Muller cells. The RDH10 protein levels in mouse eyecups and bo Show more
To investigate the expression of RDH10, an all-trans retinol dehydrogenase identified in the retinal pigment epithelium (RPE), in retinal Muller cells. The RDH10 protein levels in mouse eyecups and bovine tissues were examined by Western blot analysis using a polyclonal antibody against RDH10. The cellular localization in the retina was determined by immunohistochemistry. Expression of RDH10 in rMC-1, a cell line derived from rat Muller cells, was determined by RT-PCR and Western blot analysis. All-trans retinol dehydrogenase activity assays were performed using lysates from rMC-1 cells. The generation of all-trans retinal from tritiated all-trans retinol was analyzed by HPLC. RDH10, retinal G protein-coupled receptor (RGR), and RPE65 all had higher expression levels in the eyecups of BALB/c than in C57Bl/6 mice. In addition to the RPE, RDH10 was also detected at lower levels in the retina and liver. Immunohistochemistry showed that RDH10 was localized in Muller cells in retinal sections. RDH10 was detected in rMC-1 cells, at both the RNA and protein levels. The rat RDH10 cDNA containing the full-length coding region was cloned from rMC-1 cells. The rat RDH10 cDNA encodes a protein of 341 amino acids and shares 99% sequence identity with human, bovine, and mouse RDH10 at the amino acid level. In rMC-1 cells, all-trans retinol dehydrogenase activity was detected in the microsomal fraction. NADP was shown to be the preferred cofactor, which is identical with the cofactor preference of the recombinant RDH10. RDH10 was expressed in retinal Muller cells, in addition to the RPE. RDH10 generates all-trans retinal, which is the substrate for the photoisomerase RGR in Muller cells. Show less
Interest in mapping genetic variants that are associated with obesity remains high because of the increasing prevalence of obesity and its complications worldwide. Data on genetic determinants of obes Show more
Interest in mapping genetic variants that are associated with obesity remains high because of the increasing prevalence of obesity and its complications worldwide. Data on genetic determinants of obesity in African populations are rare. We have undertaken a genome-wide scan for body mass index (BMI) in 182 Nigerian families that included 769 individuals. The prevalence of obesity was only 5%, yet polygenic heritability for BMI was in the expected range (0.46 +/- 0.07). Tandem repeat markers (402) were typed across the genome with an average map density of 9 cM. Pedigree-based analysis using a variance components linkage model demonstrated evidence for linkage on chromosome 7 (near marker D7S817 at 7p14) with a logarithm of odds (LOD) score of 3.8 and on chromosome 11 (marker D11S2000 at 11q22) with an LOD score of 3.3. Weaker evidence for linkage was found on chromosomes 1 (1q21, LOD = 2.2) and 8 (8p22, LOD = 2.3). Several candidate genes, including neuropeptide Y, DRD2, APOA4, lamin A/C, and lipoprotein lipase, lie in or close to the chromosomal regions where strong linkage signals were found. The findings of this study suggest that, as in other populations with higher prevalences of obesity, positive linkage signals can be found on genome scans for obesity-related traits. Follow-up studies may be warranted to investigate these linkages, especially the one on chromosome 11, which has been reported in a population at the opposite end of the BMI distribution. Show less
Janet Y Leung, Frank T Kolligs, Rong Wu+5 more · 2002 · The Journal of biological chemistry · American Society for Biochemistry and Molecular Biology · added 2026-04-24
The Wnt pathway regulates cell fate, proliferation, and apoptosis, and defects in the pathway play a key role in many cancers. Although Wnts act to stabilize beta-catenin levels in the cytosol and nuc Show more
The Wnt pathway regulates cell fate, proliferation, and apoptosis, and defects in the pathway play a key role in many cancers. Although Wnts act to stabilize beta-catenin levels in the cytosol and nucleus, a multiprotein complex containing adenomatous polyposis coli, glycogen synthase kinase 3beta, and Axin1 or its homolog Axin2/Axil/conductin promotes beta-catenin phosphorylation and subsequent proteasomal degradation. We found that the rat Axil gene was strongly induced upon neoplastic transformation of RK3E cells by mutant beta-catenin or gamma-catenin or after ligand-induced activation of a beta-catenin-estrogen receptor fusion protein. Expression of Wnt1 in murine breast epithelial cells activated the conductin gene, and human cancers with defective beta-catenin regulation had elevated AXIN2 gene and protein expression. Expression of AXIN2/Axil was strongly repressed in cancer cells by restoration of wild type adenomatous polyposis coli function or expression of a dominant negative form of T cell factor (TCF)-4. TCF binding sites in the AXIN2 promoter played a key role in the ability of beta-catenin to activate AXIN2 transcription. In contrast to AXIN2/Axil, expression of human or rat Axin1 homologs was nominally affected by beta-catenin-TCF. Because Axin2 can inhibit beta-catenin abundance and function, the data implicate AXIN2 in a negative feedback pathway regulating Wnt signaling. Additionally, although Axin1 and Axin2 have been thought to have comparable functions, the observation that Wnt pathway activation elevates AXIN2 but not AXIN1 expression suggests that there may be potentially significant functional differences between the two proteins. Show less
Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by growth of benign bone tumors. This genetically heterozygous disease comprises three chromosomal loci: the EXT1 ge Show more
Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by growth of benign bone tumors. This genetically heterozygous disease comprises three chromosomal loci: the EXT1 gene on chromosome 8q23-q24, EXT2 on 11p11-p13, and EXT3 on 19p. Both EXT1 and EXT2 have been cloned and defined as a new family of potential tumor suppressor genes in previous work. However, no studies have been conducted in the Taiwanese population. To determine if previous results can also be applied to the Taiwanese, we analyzed 5 Taiwanese probands with clinical features of HME: 1 of them is a sporadic case, and the others are familial cases. Linkage studies were performed in the familial cases before the mutation analysis to determine to which of the three EXT chromosomes these cases could be assigned. Our results showed that one proband is linked to the EXT1 locus and three are linked to the EXT2 locus; the sporadic case was subsequently found to involve EXT1. We then identified four new mutations that have not been found in other races: two in EXT1--frameshift (K218fsX247) and nonsense (Y468X) mutations and two in EXT2-missense (R223P) and nonsense (Y394X) mutations. Our results indicate that in familial cases, linkage analysis can prove useful for preimplantation genetic diagnosis. Show less
17beta-Hydroxysteroid dehydrogenase type 3 (17beta-HSD-3) is a member of the short-chain dehydrogenase/reductase (SDR) family and is essential for the reductive conversion of inactive C(19)-steroid, a Show more
17beta-Hydroxysteroid dehydrogenase type 3 (17beta-HSD-3) is a member of the short-chain dehydrogenase/reductase (SDR) family and is essential for the reductive conversion of inactive C(19)-steroid, androstenedione, to the biologically active androgen, testosterone, which plays a central role in the development of the male phenotype. Mutations that inactivate this enzyme give rise to a rare form of male pseudohermaphroditism, referred to as 17beta-HSD-3 deficiency. One such mutation is the replacement of arginine at position 80 with glutamine, compromising enzyme activity by increasing the cofactor binding constant 60-fold. In the absence of a 17beta-HSD-3 crystal structure, we have grafted its amino acid sequence for the NADPH binding site on the X-ray crystal structures of glutathione reductase (Protein Data Bank code 1gra) and 17beta-HSD type 1 (Protein Data Bank codes 1fdv and 1fdu) where we find the trunk of the arginine 80 side chain forms part of the hydrophobic pocket for the purine ring of adenosine while its guanidinium moiety interacts with the 2'-phosphate to both stabilize cofactor binding and neutralize its intrinsic negative charge through two hydrogen bonds. To qualitatively assess the role arginine 80 plays in both selecting and stabilizing NADPH binding, it was replaced with each amino acid and the mutant enzymes subjected to enzymatic analysis. There are only seven enzymes exhibiting any measurable enzymatic activity with arginine approximately lysine>leucine>glutamine>methionine>tyrosine>isoleucine. With an aspartic acid at position 58 in 17beta-HSD-3 occupying the equivalent space in the cofactor binding pocket as arginine 224 in glutathione reductase or serine 12 in 17beta-HSD-1, there was an expectation that some of the mutants might use NADH as a cofactor. In no case was NADH found to substitute for NADPH. Show less
Clinical and molecular findings suggest that the four major histological subtypes of ovarian carcinoma (serous, clear cell, mucinous, and endometrioid) likely represent distinct disease entities. Prio Show more
Clinical and molecular findings suggest that the four major histological subtypes of ovarian carcinoma (serous, clear cell, mucinous, and endometrioid) likely represent distinct disease entities. Prior studies have shown that ovarian endometrioid adenocarcinomas (OEAs) often carry mutations in the CTNNB1 gene, which encodes beta-catenin, a critical component of the Wnt signaling pathway. However, the nature of other defects in the Wnt signaling pathway in ovarian carcinomas remains largely unknown. Thus, in 45 primary OEAs and two OEA-derived cell lines, we sought to comprehensively address the prevalence of and mechanisms underlying beta-catenin and Wnt pathway deregulation. CTNNB1 missense mutations were detected in 14 primary tumors. All mutations affected the NH(2)-terminal regulatory domain of beta-catenin, presumably rendering the mutant proteins resistant to degradation. Immunohistochemical studies revealed nuclear accumulation of beta-catenin in all but two tumors with CTNNB1 mutations. Two primary tumors lacking CTNNBI mutations showed strong nuclear immunoreactivity for beta-catenin. In one of the two tumors, biallelic inactivation of the APC gene was found. In the remaining 29 primary OEAs, unequivocal nuclear beta-catenin immunoreactivity was not observed, though a nonsense mutation in AXIN1 was observed in one tumor and a truncating frameshift mutation in AXIN2 was seen in another case. Both OEA-derived cell lines studied (TOV-112D and MDAH-2774) had elevated constitutive T-cell factor/lymphoid enhancer factor transcriptional activity. TOV-112D cells were shown to harbor mutant beta-catenin, whereas a missense AXIN1 sequence alteration was identified in MDAH-2774 cells. Collectively, our findings demonstrate frequent defects of the Wnt signaling pathway in a particular subtype of ovarian carcinomas, i.e., OEAs. Although mutations in the CTNNB1 gene are the most common mechanism of beta-catenin deregulation in OEAs, beta-catenin deregulation may also result from mutations in the APC, AXIN1, and AXIN2 genes. Show less
Hereditary multiple exostoses (EXT) is an autosomal dominant disease characterized by the formation of cartilage-capped prominences (exostoses) that develop from the juxta-epiphyseal regions of the lo Show more
Hereditary multiple exostoses (EXT) is an autosomal dominant disease characterized by the formation of cartilage-capped prominences (exostoses) that develop from the juxta-epiphyseal regions of the long bones. 3 genes are known to be involved in the formation of exostoses. Among them, EXT1 and EXT2, which encode enzymes that catalyse the biosynthesis of heparan sulfate, an important component of the extracellular matrix, are responsible for over 70% of the EXT cases. A large Chinese family with hereditary multiple exostoses has been analysed and the disease-causing mutation has been found. Blood samples were obtained from 69 family members, including 23 affected individuals. The EXT phenotype was shown to be linked to the EXT2 gene by using 2-point linkage analysis. After polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis and DNA sequencing, a previously unreported deletion of a G in exon 3 of EXT2 gene was observed. This deletion co-segregated with the disease phenotype, suggesting that it is the disease-causing mutation in this family. Furthermore, in at least 4 members chondrosarcoma occurred after either an operation or injury of the exostosis and 3 of them died of the malignancy in the family. Whether the operation or injury was responsible for the malignant transformation still needs further study. Show less
Wnt proteins transduce their signals through dishevelled (Dvl) proteins to inhibit glycogen synthase kinase 3beta (GSK), leading to the accumulation of cytosolic beta-catenin and activation of TCF/LEF Show more
Wnt proteins transduce their signals through dishevelled (Dvl) proteins to inhibit glycogen synthase kinase 3beta (GSK), leading to the accumulation of cytosolic beta-catenin and activation of TCF/LEF-1 transcription factors. To understand the mechanism by which Dvl acts through GSK to regulate LEF-1, we investigated the roles of Axin and Frat1 in Wnt-mediated activation of LEF-1 in mammalian cells. We found that Dvl interacts with Axin and with Frat1, both of which interact with GSK. Similarly, the Frat1 homolog GBP binds Xenopus Dishevelled in an interaction that requires GSK. We also found that Dvl, Axin and GSK can form a ternary complex bridged by Axin, and that Frat1 can be recruited into this complex probably by Dvl. The observation that the Dvl-binding domain of either Frat1 or Axin was able to inhibit Wnt-1-induced LEF-1 activation suggests that the interactions between Dvl and Axin and between Dvl and Frat may be important for this signaling pathway. Furthermore, Wnt-1 appeared to promote the disintegration of the Frat1-Dvl-GSK-Axin complex, resulting in the dissociation of GSK from Axin. Thus, formation of the quaternary complex may be an important step in Wnt signaling, by which Dvl recruits Frat1, leading to Frat1-mediated dissociation of GSK from Axin. Show less
When Saccharomyces cerevisiae cells are transferred from poor medium to fresh medium containing glucose, they rapidly increase the transcription of a large group of genes as they resume rapid growth a Show more
When Saccharomyces cerevisiae cells are transferred from poor medium to fresh medium containing glucose, they rapidly increase the transcription of a large group of genes as they resume rapid growth and accelerate progress through the cell cycle. Among those genes induced by glucose is CLN3, encoding a G(1) cyclin that is thought to play a pivotal role in progression through Start. Deletion of CLN3 delays the increase in proliferation normally observed in response to glucose medium. ADA2 and ADA3/NGG1 are necessary for the rapid induction of CLN3 message levels in response to glucose. Loss of either ADA2 or ADA3/NGG1 also affects a large number of genes and inhibits the rapid global increase in transcription that occurs in response to glucose. Surprisingly, these effects are transitory, and expression of CLN3 and total poly(A)(+) RNA appear normal when ADA2 or ADA3/NGG1 deletion mutants are examined in log-phase growth. These results indicate a role for ADA2 and ADA3/NGG1 in allowing rapid transcriptional responses to environmental signals. Consistent with the role of the Ada proteins in positive regulation of CLN3, deletion of RPD3, encoding a histone deacetylase, prevented the down regulation of CLN3 mRNA in the absence of glucose. Show less
In order to establish the rat testis as a model system for studying the human pregnancy-specific beta1-glycoprotein (PSG), expression and cellular distribution of PSG in rat testis were examined. Thre Show more
In order to establish the rat testis as a model system for studying the human pregnancy-specific beta1-glycoprotein (PSG), expression and cellular distribution of PSG in rat testis were examined. Three partial PSG cDNAs, namely, rnCGM6, rnGCM7, and rnCGM8 were obtained when rat testis cDNA libraries were screened with a human placental PSG cDNA probe. Unlike the human PSGs, the rat PSGs show less nucleotide and amino acid sequence homology among family members. The rat PSGs also have multiple truncated leader sequences followed by immunoglobulin variable-like N domains while human PSGs have a single N domain. Examination of the testis, intestine, kidney, liver, lung, and muscle of male rats by reverse transcription-polymerase chain reaction (RT-PCR) with nested gene-specific primers showed that rnCGM6 was present only in the testis, while rnCGM8 was present in the testis, intestine and lung. On the other hand rnCMG7 was found in all tissues examined. Furthermore, rnCGM7 transcript was present in all somatic cells examined whereas rnCGM6 was predominantly in myoid cells and rnCMG8 in Leydig cells. These results suggest that there is cell-specificity in the expression of PSGs in the rat testis and that the rat testis is a good model for studying the biological activities of the PSGs. Show less
Neuronal nitric oxide synthase (nNOS) is concentrated at synaptic junctions in brain and motor endplates in skeletal muscle. Here, we show that the N-terminus of nNOS, which contains a PDZ protein mot Show more
Neuronal nitric oxide synthase (nNOS) is concentrated at synaptic junctions in brain and motor endplates in skeletal muscle. Here, we show that the N-terminus of nNOS, which contains a PDZ protein motif, interacts with similar motifs in postsynaptic density-95 protein (PSD-95) and a related novel protein, PSD-93.nNOS and PSD-95 are coexpressed in numerous neuronal populations, and a PSD-95/nNOS complex occurs in cerebellum. PDZ domain interactions also mediate binding of nNOS to skeletal muscle syntrophin, a dystrophin-associated protein. nNOS isoforms lacking a PDZ domain, identified in nNOSdelta/delta mutant mice, do not associate with PSD-95 in brain or with skeletal muscle sarcolemma. Interaction of PDZ-containing domains therefore mediates synaptic association of nNOS and may play a more general role in formation of macromolecular signaling complexes. Show less
ZPR1 is a zinc finger protein that binds to the cytoplasmic tyrosine kinase domain of the epidermal growth factor receptor (EGFR). Deletion analysis demonstrated that this binding interaction is media Show more
ZPR1 is a zinc finger protein that binds to the cytoplasmic tyrosine kinase domain of the epidermal growth factor receptor (EGFR). Deletion analysis demonstrated that this binding interaction is mediated by the zinc fingers of ZPR1 and subdomains X and XI of the EGFR tyrosine kinase. Treatment of mammalian cells with EGF caused decreased binding of ZPR1 to the EGFR and the accumulation of ZPR1 in the nucleus. The effect of EGF to regulate ZPR1 binding is dependent on tyrosine phosphorylation of the EGFR. ZPR1 therefore represents a prototype for a class of molecule that binds to the EGFR and is released from the receptor after activation. Show less
Cyclins constitute a growing family of regulatory proteins that complex with, and activate, protein kinases involved in cell cycle control. Dysregulation of cyclin expression and/or cyclin-dependent k Show more
Cyclins constitute a growing family of regulatory proteins that complex with, and activate, protein kinases involved in cell cycle control. Dysregulation of cyclin expression and/or cyclin-dependent kinase (cdk) activities may play a pivotal role in oncogenesis. In this report, we characterize a novel human cyclin gene by molecular cloning. This gene, designated CYCG1, encodes a human homologue of the rat G-type cyclin, exhibiting structural features and conserved sequence motifs of identified G(1) cyclins. The CYCG1 gene is expressed constitutively in synchronized human WI-38 fibroblasts and MG-63 osteosarcoma cells, which is reminiscent of CLN3 in Saccharomyces cerevisiae. Marked overexpression of CYCG1 is observed in a subset of human osteosarcoma cells, providing a potential link to cancer. Show less
Chromosomal locations of 10 isozyme loci in rice (Oryza sativa L.) were determined through trisomic analysis. All 10 genes produced altered allozyme banding patterns in specific F1 trisomics. This ser Show more
Chromosomal locations of 10 isozyme loci in rice (Oryza sativa L.) were determined through trisomic analysis. All 10 genes produced altered allozyme banding patterns in specific F1 trisomics. This served as the primary source of evidence for chromosome locations of Est-5, Icd-1, Acp-1, and Pgd-1. The locations of Amp-1, Amp-2, Amp-4, Pox-5, Got-1, and Cat-1 were further confirmed from segregation data in BC1 generations, as the ratios deviated significantly from 1:1 in the critical trisomics but agreed with the expected trisomic ratios. Triallelic heterozygotes were recovered for Amp-1 and Amp-2. On the basis of these data Got-1, Est-5, and Icd-1 were located to chromosome 1, Amp-1 to chromosome 2, Cat-1 and Pox-5 to chromosome 3, Acp-1 to chromosome 6, Amp-2 and Amp-4 to chromosome 8, and Pgd-1 to chromosome 11. Because Acp-2 and Pox-2 are known to be linked with Acp-1, they must also be on chromosome 6. The gene order and recombination values between isozyme loci on chromosomes 3, 6, 8, and 11 are presented. Show less
S Li, E L Ma, S J Wu · 1988 · Scientia Sinica. Series B, Chemical, biological, agricultural, medical & earth sciences · added 2026-04-24
Nuclei from the normal mouse liver were partially digested with micrococcal nuclease, followed by DNA extraction, agarose gel electrophoresis and dot blot hybridization with 32P-labeled cDNA probes of Show more
Nuclei from the normal mouse liver were partially digested with micrococcal nuclease, followed by DNA extraction, agarose gel electrophoresis and dot blot hybridization with 32P-labeled cDNA probes of CPS1 and ACT complex. It was clearly shown that the CPS1 genes were distributed on the monomer, dimer. and trimer of nucleosomes, while the genes coding for ACT complex were distributed on the condensed oligonucleosomes. An opposite manner of distribution of CPS1 and ACT complex genes was, however, noted in the case of ascites hepatoma cells, in which the specific activity of ACT was 13 times higher than that in the normal liver, while that of CPS1 was remarkably reduced. Similar patterns of change in mRNA level of CPS1 and ACT complex were observed in the normal mouse liver and ascites hepatoma cells, indicating a close relationship between chromatin structure and gene expression of these enzymes. Show less
S J Wu, S E Li · 1988 · Scientia Sinica. Series B, Chemical, biological, agricultural, medical & earth sciences · added 2026-04-24
With cDNA fragments of CPS1, OCT and ACT as probes, dot and Northern blot analyses of poly(A)+-RNA from rat liver with different pathological lesions during carcinogenesis induced by diethylnitrosamin Show more
With cDNA fragments of CPS1, OCT and ACT as probes, dot and Northern blot analyses of poly(A)+-RNA from rat liver with different pathological lesions during carcinogenesis induced by diethylnitrosamine were conducted. It was shown that the level of mRNA of tissue-specific enzymes, CPSI and OCT decreased while that of the proliferating enzyme ACT mRNA increased, and the alteration was correlated with the degree of pathological changes in each case. The relative changes in the mRNA level of these enzymes during hepatocarcinogenesis were correlated with that of enzyme activities. Implication of these findings in the mechanism of carcinogenesis in terms of cell proliferation and differentiation was discussed. Show less
cDNA coding for carbamyl phosphate synthetase I was cloned from recombinant plasmid with insert complementary to the mRNA for CPS1 followed by hybrid-selected translation screening. The length of the Show more
cDNA coding for carbamyl phosphate synthetase I was cloned from recombinant plasmid with insert complementary to the mRNA for CPS1 followed by hybrid-selected translation screening. The length of the insert CPS1 cDNA was approximately 800 base pairs. Using this cDNA as a probe, it was found by dot-blot analysis of the total RNAs and poly(A)+-RNAs isolated from rat livers with different pathological lesions induced by diethylnitrosamine that the levels of CPS1 mRNA were decreased, the decrease being correlated with the malignancy of hepatocytes during carcinogenesis. Show less
The acid phosphatase (AcP) isoenzyme in a human prostatic cancer cell line was compared to that of prostatic tissue extract by electrophoresis. The major isoenzyme by prostatic tissue extract is the A Show more
The acid phosphatase (AcP) isoenzyme in a human prostatic cancer cell line was compared to that of prostatic tissue extract by electrophoresis. The major isoenzyme by prostatic tissue extract is the AcP isoenzyme 2, while only AcP isoenzyme 4 (AcP-4) was observed in the human prostatic cancer cell line. A monoclonal antibody specific to AcP-4 was used to investigate the ultrastructural distribution of AcP-4 in a prostatic cancer cell line. The peroxidase staining pattern indicates that AcP-4 is synthesized on bound ribosomes, discharged into the cisternae of rough endoplasmic reticulum, transported to the cisternae of Golgi apparatus for concentration and packaging, and transferred to the secretory vesicles for exocytosis. It is well known that synthesis and secretion of AcP-2 are the major characteristics of the highly differentiated prostatic epithelial cells. The present data demonstrate the loss of this specific function in the prostatic cancer cell line. Instead of AcP-2, the dedifferentiated cancer cell line synthesizes and secretes AcP-4, which is a common AcP isoenzyme of many nonprostatic tissues. Show less