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Biomedical subjects

G An

Publications and source records attributed to G An.

At least 19 recordsLinked to original sources
PubMed1995

Two nuclear proteins in tracheal epithelial cells are recognized by antibodies specific to a squamous differentiation marker, sprI.

In cell-free translations of RNA from primary cultures of pig trachea surface epithelial cells we observed that a mRNA encoding a 20 kDa proline-rich protein (sPRP) was dramatically induced during culturing (Tesfaigzi et al., 1990, Biochem. Biophys. Res. Commun., 172:M1304-1309). This mRNA was not detected in tracheal tissue or in epithelial cells prior to culturing. Antisera were raised to synthetic peptide sequences corresponding to 23 amino acids on the C-terminus (C23-antiserum) and 29 amino acids on the N-terminus (N29 antiserum) of sPRP. On Western blot analysis, C23 antiserum reacted with a 20 kDa protein in cytosolic extracts from pig tracheal cells maintained in culture for 4 days. The reaction with the 20 kDa protein was inhibited by adding C23 peptide. Two nuclear proteins (66 and 70 kDa) obtained by micrococcal nuclease treatment of tracheal cell nuclei were detected on Western blots with C23 antiserum. These proteins were present in cells both before and after culturing. Sucrose gradient fractionation indicated that these nuclear proteins are associated with chromatin. Small amounts of the 66 and 70 kDa proteins were obtained from nuclear matrix fractions. These nuclear proteins also reacted with N29 antiserum. Since these proteins share similar epitopes with the N- and C-termini of sPRP, it is likely that the 20 kDa protein (sPRP) is part of these proteins. However, purification of the nuclear proteins followed by an amino acid sequence analysis is necessary to clarify whether sPRP is part of these proteins.

Amino Acid Sequence↗
PubMed1995

Phenotypic alterations of petal and sepal by ectopic expression of a rice MADS box gene in tobacco.

Floral organ development is controlled by a group of regulatory factors containing the MADS domain. In this study, we have isolated and characterized a cDNA clone from rice, OsMADS3, which encodes a MADS-domain containing protein. The OsMADS3 amino acid sequence shows over 60% identity to AG of Arabidopsis, PLE of Antirrhinum majus, and AG/PLE homologues of petunia, tobacco, tomato, Brassica napus, and maize. Homology in the MADS box region is most conserved. RNA blot analysis indicated that the rice MADS gene was preferentially expressed in reproductive organs, especially in stamen and carpel. In situ localization studies showed that the transcript was present primarily in stamen and carpel. The function of the rice OsMADS3 was elucidated by ectopic expression of the gene under the control of the CaMV 35S promoter in a heterologous tobacco plant system. Transgenic plants exhibited an altered morphology and coloration of the perianth organs. Sepals were pale green and elongated. Limbs of the corolla were split into sections which in some plants became antheroid structures attached to tubes that resembled filaments. The phenotypes mimic the results of ectopic expression of dicot AG gene or AG homologues. These results indicate that the OsMADS3 gene is possibly an AG homologue and that the AG genes appear to be structurally and functionally conserved between dicot and monocot.

Amino Acid Sequence↗
PubMed1995

Calmodulin gene family in potato: developmental and touch-induced expression of the mRNA encoding a novel isoform.

Eight genomic clones of potato calmodulin (PCM1 to 8) were isolated and characterized. Sequence comparisons of different genes revealed that the deduced amino acid sequence of PCM1 had several unique substitutions, especially in the fourth Ca(2+)-binding area. The expression patterns of different genes were studied by northern analysis using the 3'-untranslated regions as probes. The expression of PCM1, 5, and 8 was highest in the stolon tip and it decreased during tuber development. The expression of PCM6 did not vary much in the tissues tested, except in the leaves, where the expression was lower; whereas, the expression of PCM4 was very low in all the tissues. The expression of PCM2 and PCM3 was not detected in any of the tissues tested. Among these genes, only PCM1 showed increased expression following touch stimulation. To study the regulation of PCM1, transgenic potato plants carrying the PCM1 promoter fused to the beta-glucuronidase (GUS) reporter gene were produced. GUS expression was found to be developmentally regulated and touch-responsive, indicating a positive correlation between the expression of PCM1 and GUS mRNAs. These results suggest that the 5'-flanking region of PCM1 controls developmental and touch-induced expression. X-Gluc staining patterns revealed that GUS localization is high in meristematic tissues such as the stem apex, stolon tip, and vascular regions.

Amino Acid Sequence↗
PubMed1995

Study of the optimal duration of preoxygenation in children.

STUDY OBJECTIVE: To determine the optimal length of preoxygenation in children. DESIGN: Random design and comparison among groups. SETTING: Operating room of a plastic surgery hospital of the Chinese Academy of Medical Sciences and the Peking Union Medical College. PATIENTS: Forty healthy, ASA status 1 children (age 2 to 7 yrs), undergoing elective plastic surgery. INTERVENTIONS: Children in Group 1 breathed 100% oxygen (O2) for 1 minute. Group 2 children breathed 100% O2 for 2 minutes. Group 3 and Group 4 children breathed 100% O2 for 3 minutes. Anesthesia was induced with midazolam 0.3 mg/kg, fentanyl 5 micrograms/kg. Muscle relaxation was achieved with vecuronium 0.1 mg/kg (Groups 1, 2, and 3) or succinylcholine 1.5 mg/kg (Group 4). MEASUREMENTS AND MAIN RESULTS: Oxygen saturation (SpO2) was measured by pulse oximeter. The oximeter probe was applied to the right big toe. After preoxygenation, the times for SpO2 to decrease to 98% (T98), 95% (T95), and 90% (T90), respectively, were recorded during the apneic period. T98, T95, and T90 were significantly shorter in Group 1 than in Group 2 or Group 3. There was no statistically significant difference among Groups 2, 3, or 4 regarding T98, T95, and T90. The times for SpO2 to decrease from 95% to 90% were similar among the four groups. CONCLUSIONS: 2 minutes of preoxygenation in children can provide the maximum benefit of denitrogenation and achieve 2 minutes of safe apea. 95% and 99% confidence intervals were 69 to 100 and 59 to 100, respectively. Succinylcholine had only a slight effect on the safe apneic period.

Anesthesia↗
PubMed1994

Early flowering and reduced apical dominance result from ectopic expression of a rice MADS box gene.

Recent studies with dicot plants reveal that floral organ development is controlled by a group of regulatory factors containing the MADS domain. In this study, we have isolated and characterized a cDNA clone from rice, OsMADS1, which encodes a MADS-domain-containing protein. The OsMADS1 amino acid sequence shows 56.2% identity to AGL2 and 44.4% identity to AP1. The MADS box region was the most homologous to other MADS-domain-containing proteins. Northern blot analysis indicated that the rice MADS gene was preferentially expressed in floral organs. In situ localization studies showed that the transcript was uniformly present in young flower primordia and later became localized in palea, lemma, and ovary. Ectopic expression of OsMAD1 with the CaMV 35S promoter in transgenic tobacco plants dramatically alters development, resulting in short, bushy, early-flowering plants with reduced apical dominance. These results suggest that the OsMADS1 gene is involved in flower induction and that it may be used for genetic manipulation of certain plant species.

Amino Acid Sequence↗
PubMed1993

Expression of c-fos and c-jun family genes after focal cerebral ischemia.

The expression of the protooncogenes, c-fos, jun B, c-jun, and jun D was investigated in a rat focal cerebral ischemia model by Northern analysis and in situ hybridization. Severe ischemia (reduction of regional blood flow by 88-92%) in this model is confined to cerebral cortex irrigated by the right middle cerebral artery. Ischemia for 30 minutes, which caused only slight cortical damage (infarct size, < 10 mm3), induced both jun B and c-fos mRNAs exclusively in the right cerebral cortex. Ischemia for 90 minutes, which led to large cortical infarction (infarct size, > 140 mm3), also induced the expression of these two genes in the right cerebral cortex as well as the ipsilateral hippocampus. The latter sustained very mild ischemia (reduction of regional blood flow by 10-20%). The coinduction of jun B and c-fos expression occurred immediately after reperfusion and peaked at 60 minutes after reperfusion. The expression of c-jun was enhanced in a similar pattern, but at a much lower magnitude. In contrast, no change in jun D expression was observed. Nuclear run-on assays indicated that the increase in c-fos, jun B, and c-jun mRNA levels was due to the increase of transcription rate in these genes. Mobility shift assays showed a basal DNA binding activity of transcription factor AP-1 in the right cerebral cortex. Ischemia for 30 or 90 minutes followed by reperfusion for 4 hours resulted in a four- to sixfold increase of AP-1 binding activity. The enhanced DNA binding activity persisted for as long as 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Induction of Krox-20 expression after focal cerebral ischemia.

Krox-20 is one of the transcription factors of "zinc finger" family. The expression of Krox-20 was investigated in a rat focal cerebral ischemia model by Northern blot analysis and in situ hybridization. Northern blot analysis showed that ischemia for 30 min which caused little cortical infarction induced a 29-fold increase in Krox-20 mRNA signal exclusively in the ischemic cortex. Ischemia for 90 min which led to large cortical infarction induced Krox-20 mRNA not only in the ischemic cortex but also in the ipsilateral hippocampus. The induction of Krox-20 mRNA was rapid, transient and appeared to be controlled at the transcriptional level, as indicated by nuclear run-on assays. The regional induction of Krox-20 mRNA was further confirmed by in situ hybridization. These results suggest that the expression of transcription factor genes may play a role in the post-ischemic changes of the injured brain.

Brain Ischemia↗
PubMed1992

Cloning of the cDNA for U1 small nuclear ribonucleoprotein particle 70K protein from Arabidopsis thaliana.

We cloned and sequenced a plant cDNA that encodes U1 small nuclear ribonucleoprotein (snRNP) 70K protein. The plant U1 snRNP 70K protein cDNA is not full length and lacks the coding region for 68 amino acids in the amino-terminal region as compared to human U1 snRNP 70K protein. Comparison of the deduced amino acid sequence of the plant U1 snRNP 70K protein with the amino acid sequence of animal and yeast U1 snRNP 70K protein showed a high degree of homology. The plant U1 snRNP 70K protein is more closely related to the human counter part than to the yeast 70K protein. The carboxy-terminal half is less well conserved but, like the vertebrate 70K proteins, is rich in charged amino acids. Northern analysis with the RNA isolated from different parts of the plant indicates that the snRNP 70K gene is expressed in all of the parts tested. Southern blotting of genomic DNA using the cDNA indicates that the U1 snRNP 70K protein is coded by a single gene.

Amino Acid Sequence↗
PubMed1992

Thioredoxin gene expression is transcriptionally up-regulated by retinol in monkey conducting airway epithelial cells.

Using the differential hybridization technique, a cDNA clone, MT78, was isolated from the cDNA library of retinol-treated monkey tracheobronchial (TBE) epithelial cells. MT78 has a high sequence homology to human thioredoxin. The cDNA insert contains 506 nucleotides which encodes a peptide of 105 amino acids. The deduced peptide contains the highly conserved sequence Cys-Gly-Pro-Cys, found at the active site of all thioredoxins. The expression of the thioredoxin gene is stimulated 8-10 fold by vitamin A (retinol) in monkey TBE cells. The expression is significantly enhanced within 4 h after the vitamin A treatment and concurrent protein synthesis is not required for this enhancement. These results, in conjunction with the nuclear run-on transcriptional assay, support the conclusion that thioredoxin gene is transcriptionally up-regulated by retinol and/or its metabolites.

Amino Acid Sequence↗
PubMed1992

Effect of deletions 5' to the translation initiation sequence on the expression of an mRNA in animal cells.

To learn if an mRNA.18S rRNA interaction or a special secondary structure in the mRNA start region is essential for translation in eukaryotic cells, we constructed recombinant plasmids with the SV40 early promoter 5' to part of the Escherichia coli tufB-lacZ gene. Deletion of bases potentially complementary to the 18S rRNA highly increased the transient beta-galactosidase expressed in transfected CHO cells. Deletion of bases that fostered formation of potential hairpins with the mRNA 5'-terminus or altered the structure of the coding region reduced beta-galactosidase activity suggesting that these features of the mRNA secondary structure may be essential for initiation of translation. Computer aided analysis of the potential structure of 290 mRNAs suggests these are conserved features of the initiation region.

Animals↗
PubMed1992

Pollen-specific expression of the Arabidopsis thaliana alpha 1-tubulin promoter assayed by beta-glucuronidase, chloramphenicol acetyltransferase and diphtheria toxin reporter genes.

We have characterized the promoter specificity of the Arabidopsis thaliana alpha 1-tubulin (alpha 1-tub) gene by studying expression patterns of gene fusions between the 2.2 kbp 5' upstream region of the alpha 1-tub gene and each of three different reporters: chloramphenical acetyltransferase, beta-glucuronidase or the diphtheria toxin chain A gene. Analysis of transgenic tobacco and Arabidopsis plants carrying the transgene showed that the chloramphenicol acetyltransferase and beta-glucuronidase activities were not detected in any vegetative or reproductive organs except mature pollen. Transgenic tobacco plants carrying the diphtheria toxin chain A gene under the control of the alpha 1-tub promoter were of normal phenotype but seed fertility was drastically reduced. Furthermore, the transgene could not be transmitted to the next generation through pollen, supporting the observation that the alpha 1-tub promoter is active only in pollen. It was observed that the promoter activity was most active in mature pollen and decreased significantly during in vitro pollen germination, indicating that the promoter is inactive or subdued in germinating pollen. The promoter activity was not affected by various plant growth hormones during pollen maturation.

Arabidopsis↗
PubMed1992

An unusual expression of a squamous cell marker, small proline-rich protein gene, in tracheobronchial epithelium: differential regulation and gene mapping.

An unusual expression of a putative squamous cell marker, small proline-rich protein (spr1), in mucociliary epithelial cells of conducting airways was demonstrated in a serum-free culture system. A cDNA clone was isolated from the cDNA library of monkey tracheobronchial epithelial (TBE) cells by differential hybridization. This cDNA clone, MT5, exhibited 98% homology to a DNA sequence obtained from human keratinocytes treated with either UV light or phorbol esters (T. Kartasova et al., 1988, Mol. Cell. Biol. 8:2195-2230). The predicted peptide of MT5 is unusual for its high content of proline (29%), glutamine (18%), and cysteine (9%) and its repeated PKVPEPC units. The level of spr1 mRNA in cultured cells was inhibited more than 90% by vitamin A. In contrast, phorbol 12-myristate 13-acetate (PMA) stimulated the level of spr1 mRNA by 3- to 8-fold. This differential regulation coincided with the effects of these chemicals on the cornification of cultured TBE cells. Using MT5 as a probe, we have localized the tracheal spr1 gene on the human chromosome 1 by a Southern blot analysis using a panel of human-rodent somatic cell hybrid DNAs. The gene was further sublocalized to bands q22-23 by in situ hybridization.

Amino Acid Sequence↗
PubMed1991

Structural and functional analysis of promoter from gliadin, an endosperm-specific storage protein gene of Triticum aestivum L.

To identify cis-regulatory elements of the gliadin gene, a study of the gliadin gene promoter was conducted by transient expression analysis of plasmid DNAs which were introduced into plant protoplasts by electroporation. The promoter region (-592 bp to +18 bp from the translational start) of this developmentally regulated gene, when fused upstream to the chloramphenicol acetyl transferase (CAT) reporter cassette was unable to direct significant CAT expression in wheat or tobacco suspension cells. Because this monocot gene promoter appeared to be under stringent tissue-specific control, a hybrid promoter approach using a nopaline synthase (nos) promoter was employed. A series of 3' deletions of the gliadin promoter were placed upstream of either a nonfunctional -101 nos or a nearly wild-type -155 nos promoter fused in turn to a CAT reporter gene cassette. Transient expression analysis of these plasmid DNAs in tobacco cells showed that the gliadin fragment could either restore the activity of the non-functional nos promoter (series I) or enhance the activity of the functional nos promoter (series II). The degree of restoration of the promoter function conferred by gliadin fragments of the first series was proportional to the enhancing effect of the same fragments in the second series of constructs. The transcriptional activity of the gliadin (-592 bp to -77 bp) -nos hybrid promoter was reduced by 26% upon 3' deletion of sequences in the region -141 bp to -77 bp, which contains both the TATA and CCAAT boxes.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1991

[Transcutaneous PO2 monitoring during cervico-thoracic epidural analgesia].

The measurement of transcutaneous oxygen tension (PtcO2) in 19 patients during cervico-thoracic epidural block with 1 percent lidocaine is reported. The data demonstrated close correlations between PtcO2 and PaO2 levels. PtcO2 in about 50 percent of the patients showed significant decreases approximately 25 minutes after epidural administration of lidocaine. Complaints of dyspnea were unrelated to PtcO2 and PaO2 levels. The authors suggest that cervico-thoracic epidural block even under low concentrations of local anesthetic (1 percent lidocaine) may depress the respiratory function after a transient interval. Great attention should be paid to the management of respiratory function during this period of time.

Adolescent↗
PubMed1990

Induction in the expression of an unusual proline-rich protein by pig tracheal surface epithelial cells maintained in primary culture.

Primary cell culture is a valuable tool for studying the regulation of gene expression since many differentiated traits are conserved. Cells cultured from the epithelial lining of pig trachea were selected as a model system for mucin synthesis. RNAs were isolated from pig trachea epithelial linings and from pig trachea surface epithelial cells cultured in serum-free media. Cell free translations showed an unusually high incorporation of [3H]proline into a relatively small protein (about 20 kDa), but only with RNA from the cells in culture. RNA prepared from pig trachea cells immediately before placing the cells in culture (day 0) did not contain mRNA encoding this unusual proline-rich protein. However, the expression of this protein was dramatically induced within 2 days of maintaining the cells in culture.

Animals↗
PubMed1990

Production of a foreign protein product with genetically modified plant cells.

Plant cells (Nicotiana tabacum) were genetically engineered to produce a foreign protein, chloramphenicol acetyltransferase (CAT), and the CAT production from suspension cultures was investigated. Suspension cultures were grown in a shake flask, a stirred fermenter, and a bubble-column fermenter. The CAT production was growth related and the maximum activity was reached during the early stationary phase. A 41-day, semicontinuous stirred fermenter run, consisting of five sequential batch runs, demonstrated long-term CAT production. Continuous CAT production was also accomplished in a bubble-column fermenter at a medium flow rate of 3.1 ml h-1, which was equivalent to a dilution rate of 0.25 day-1.

Cells, Cultured↗
PubMed1990

Wound-inducible nuclear protein binds DNA fragments that regulate a proteinase inhibitor II gene from potato.

Deletion analysis from the 3' to the 5' end of the promoter region of the wound-inducible potato proteinase inhibitor IIK gene has identified a 421-base sequence at -136 to -557 that is necessary for expression. Utilizing DNA band-shift assays, a 10-base sequence within the 421-base region was found to bind a nuclear protein from wounded tomato leaves. This 10-base sequence is adjacent to an 8-base consensus sequence at -147 to -155 that is present in the promoter region of several elicitor-inducible genes from various other plants. The evidence suggests that a complex set of cis- and trans-acting elements within the -136 to -165 region of the potato IIK gene may be involved with the signaling mechanisms that regulate the inducibility of this gene in response to pest and pathogen attacks.

Base Sequence↗