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Developmental expression analysis of the 1731 retrotransposon reveals an enhancement of Gag-Pol frameshifting in males of Drosophila melanogaster.

Extensive analyses of Drosophila melanogaster retrotransposon transcriptions in cultured cells or during development have been reported, but little is known about their translation during the development of the fly. Analysis of the translational products of the 1731 Drosophila melanogaster retrotransposon in Kc Drosophila cultured cells has been reported, showing the existence of primary products (Gag and Pol) and of processed polypeptides of various sizes. Study of 1731 retrotransposon expression at both levels of transcription and translation during the development of Drosophila melanogaster, is presented. 1731 transcripts were detected by in situ hybridization and 1731 proteins were detected by immunostaining and immunoblotting in embryos and in adult gonads. 1731 transcripts and proteins were detected in the mesoderm and central nervous system during embryonic development, in nurse cells and follicle cells in adult ovaries and in primary spermatocytes in adult testes. Moreover, Western blot analysis of the 1731 proteins with anti-Gag or anti-Pol antibodies in gonads revealed that the 1731 mRNA could be translated differentially according to the expressing tissue: essentially, ovarian translation and/or processing of 1731 products is different from that operating in testes, where the Gag-Pol fusion polyprotein is the most prominent product. Our results indicate that expression of the 1731 mobile element is regulated not only at the transcriptional level but also at the translational level, and that this regulation is different in the two sexes.

Animals

Molecular cloning, sequence analysis, expression, and tissue distribution of suppressin, a novel suppressor of cell cycle entry.

Suppressin (SPN) is an inhibitor of cell proliferation that was originally identified and purified to homogeneity from bovine pituitaries (LeBoeuf, R. D., Burns, J. N., Bost, K. L., and Blalock, J. E. (1990) J. Biol. Chem. 265, 158-165). In this report we have cloned the full-length cDNA encoding rat SPN and have identified the tissue distribution of SPN expression. The cDNA of SPN is 1882 nucleotides with a 1488-base coding region and 55 and 339 nucleotides of 5'- and 3'-untranslated sequences, respectively. Northern gel analysis of rat pituitary mRNA showed a single hybridizing species at approximately 2 kilobases. Sequence analyses showed that the nucleotide and deduced amino acid sequences of SPN are novel and unrelated to any known vertebrate inhibitors of proliferation. However, the deduced amino acid sequence of SPN contains two domains that have extensive sequence identity with a recently cloned transcription activator in Drosophila, deformed epidermal autoregulatory factor-1 (DEAF-1, see Gross, C. T., and McGinnis, W. (1996) EMBO J. 15, 1961-1970) suggesting that SPN represents a vertebrate cognate of deformed epidermal autoregulatory factor-1. Reverse transcriptase-polymerase chain reaction and immunohistochemical analyses showed that the SPN mRNA and the SPN protein are expressed in every tissue examined including testis, spleen, skeletal muscle, liver, kidney, heart, and brain suggesting that SPN may be involved in the control of proliferation in a variety of cell types.

Amino Acid Sequence

Movement, face processing and schizophrenia: evidence of a differential deficit in expression analysis.

Three dynamic face-processing tasks based on the Bruce & Young (1986) functional model of face processing were presented to 10 schizophrenic and 10 depressed inpatients and to 10 non-patient subjects. Familiar face recognition, facial expression recognition and unfamiliar face matching were examined. Schizophrenic patients' performance was significantly poorer than that of depressed patients and non-patient controls. Significantly lower scores were obtained on the facial expression recognition task than on the familiar face recognition task. There was a differential pattern of group performance on each of the three tasks: schizophrenic and depressed patients were as accurate as non-patient controls on the familiar face recognition task, but significantly less accurate than non-patient controls on the unfamiliar face-matching task. Schizophrenic patients were significantly less accurate than depressed patients and non-patient controls on the facial expression recognition task. The results are contrasted with an analogous static face-processing study.

Adolescent

Plant mitochondrial NAD+-dependent malic enzyme. cDNA cloning, deduced primary structure of the 59- and 62-kDa subunits, import, gene complexity and expression analysis.

The 59- and 62-kDa subunits of the mitochondrial NAD+-dependent malic enzyme (EC 1.1.1.39) were purified from Solanum tuberosum L. (potato). NH2-terminal and internal amino acid sequence information was used to identify cDNAs encoding the two subunits. Comparison of the nucleotide sequences revealed that the subunits have 60% identity at the DNA level and 65% identity at the deduced amino acid level, implying that they are derived from a common ancestral gene. The plant NAD+-dependent malic enzymes belong to a family of related enzymes, including cytosolic and chloroplastic NADP+-dependent malic enzymes (EC 1.1.1.40) and bacterial NAD+-dependent malic enzymes (EC 1.1.1.38). The cDNAs were transcribed and translated in vitro and the resultant polypeptides imported into isolated mitochondria and shown to be processed. Southern blot analysis of potato genomic DNA revealed a simple pattern of hybridization for both subunits, indicating a simple gene structure or small number of genes encoding the two subunits. Northern blot analysis of RNA from a range of potato tissues has shown that the steady state levels for the two subunits are equivalent, suggesting that they are coordinately expressed.

Amino Acid Sequence

Isolation and expression analysis of two rice genes encoding the major intrinsic protein.

We isolated two rice cDNAs (rMip1 and rTip1) which are homologous to the genes encoding the major intrinsic protein (Mip) (soybean nod-26 and Arabidopsis gamma-Tip), respectively. Expression of rTip1 in shoots and roots of rice seedlings was enhanced by water stress, salt stress and exogenous ABA. rMip1 was expressed only in shoots. Although mRNA level of rMip1 in shoots was induced to a small extent by exogenous ABA, it did not show any increase under water or salt stress over the course of 12 h. On the basis of the differential expression patterns and evolutional distinctions, it is suggested that the possible channel proteins encoded by rMip1 and rTip1 genes may function in different transport systems.

Abscisic Acid

Structure, chromosomal localization, and expression analysis of the mouse inhibin/activin beta C (Inhbc) gene.

The mouse inhibin/activin beta C gene (Inhbc), a member of the transforming growth factor-beta (TGF-beta) superfamily, was cloned, mapped, and characterized. The gene spans approximately 14 kb, is composed of two exons, and maps to the distal region of mouse chromosome 10, which is syntenic to chromosome 12q13.1, where the human inhibin/activin beta C gene (INHBC) maps. The primary translation product is a preproprotein of 352 amino acids. The mature C-terminal domain of 116 amino acids shares 94% identity with its human homolog. Primer extension analysis shows that transcription starts approximately 130 bp upstream of the translation initiation site, and no TATA box was found in the promoter. Ribonuclease protection analyses reveal that mouse Inhbc is predominantly expressed in adult liver. Embryonic expression is detected beginning from Day 14.5 of gestation.

Activins

Cloning, mapping, and expression analysis of TBX15, a new member of the T-Box gene family.

The T-box gene family has been conserved throughout metazoan evolution and codes for putative transcription factors that share a uniquely defining DNA-binding domain. We have previously uncovered six mouse T-box genes with discrete spatial and temporal patterns of expression during embryogenesis. Here, we report a novel mouse T-box gene, Tbx15. The Tbx15 gene produces a 3.7-kb transcript with an open reading frame coding for a polypeptide with 602 amino acid residues. Phylogenetic analysis places the Tbx15 gene into a T-box subfamily that also includes mouse Tbx1, Drosophila H15, and nematode Ce-tbx-12 genes. We have mapped mouse Tbx15 to chromosome 3, at a position 49 cM from the centromere. During development, Tbx15 transcripts are first detected at embryonic day 9.5. The gene is expressed primarily in the cranio-facial region and in the developing limbs. An isolated human homolog, TBX15, has been mapped by in situ hybridization to chromosomal band 1p13. TBX15 appears to be an excellent candidate for the dominantly expressed acromegaloid facial appearance syndrome, which also maps to the short arm of human chromosome 1 and, like TBX15, is expressed prominently in the eyebrow regions.

Animals

Identification and expression analysis of calcium-dependent protein kinase family in oat (Avena sativa L.) and their functions in response to saline-alkali stresses.

Calcium-dependent protein kinases (CDPKs) serve as calcium ion sensors and play crucial roles in all aspects of plant life cycle. While CDPK gene family has been extensively studied in various plants, there is limited information available for CDPK members in oat, an important cereal crop worldwide. Totally, 60 AsCDPK genes were identified in oat genome and were classified into four subfamilies based on their phylogenetic relationship. The members within each subfamily shared similar gene structure and conserved motifs. Collinearity analysis revealed that AsCDPK gene amplification was attributed to segmental duplication events and underwent strong purifying selection. AsCDPK promoters were predicted to contain cis-acting elements associated with hormones, biotic and abiotic stresses. AsCDPK gene expressions were induced by different salt stresses, exhibiting stress-specific under different salt treatments. Moreover, overexpression of AsCDPK26 gene enhanced salt resistance in C. reinhardtii, a single-cell photoautotrophic model plants. Further analysis revealed a significant correlation between AsCDPK26 and Na+/H+ antiporter 1 (p<0.05), suggesting that AsCDPK26 may interact with ion transporter to modulate salt resistance. These results not only provide valuable insights into AsCDPK genes in response to different salt stresses, but also lay the foundation to mine novel candidates for improving salt tolerance in oat and other crops.

Chlamydomonas reinhardtii

Tobacco cytochrome b5: cDNA isolation, expression analysis and in vitro protein targeting.

A full-length clone encoding cytochrome b5 has been isolated from a tobacco leaf cDNA library in lambda gt11 by PCR using degenerate primers. This cDNA encodes a protein of 139 residues which exhibits a high degree of homology to other cytochrome b5s, the message for which is expressed predominantly in developing seeds and in pigmented flower tissue. In the developing tobacco seed the mRNA is abundant at very early stages (< 10 days after flowering). Southern analysis indicated that more than one gene encodes cytochrome b5 in the tobacco genome. In vitro transcription and translation studies of the cDNA indicated that the protein inserts into the ER membrane by a non-SRP-mediated pathway and that the C-terminus of the protein is required for targeting and insertion.

Amino Acid Sequence

Cloning and expression analysis of a cDNA encoding fumarylacetoacetate hydrolase: post-transcriptional modulation in rat liver and kidney.

Fumarylacetoacetate hydrolase (FAH) is an enzyme which is deficient in human hereditary tyrosinemia type 1. We have cloned and sequenced a rat liver cDNA encoding FAH. The identity of the clone was ascertained by hybrid-selection experiments and deduced amino acid (aa) sequence homologies with sequenced oligopeptide fragments of the purified rat liver protein. The cDNA codes for a 419-aa protein of 45,946 daltons. We used this cDNA as a probe in conjunction with a specific anti-rat FAH antibody to study the expression pattern of the FAH gene in rat liver and kidney. Northern blot analysis indicates that the kidney contains slightly more FAH mRNA that the liver. Western blotting shows, however, that the liver contains about twice as much FAH protein as the kidney. Primer extension experiments suggest that there are no differences in the 5'-untranslated (UT) ends of the FAH mRNA of both tissues. We conclude that synthesis of the FAH protein is in part regulated at the post-transcriptional level in rats liver and kidney, and that this regulation does not appear to be mediated by the 5'-UT sequence of the FAH mRNA.

Amino Acid Sequence

Regulation of Actinobacillus actinomycetemcomitans leukotoxin expression: analysis of the promoter regions of leukotoxic and minimally leukotoxic strains.

The leukotoxin of Actinobacillus actinomycetemcomitans has been implicated as a virulence determinant in various human infections and is encoded by a multigene operon consisting of four known genes, designated ltxC, ltxA, ltxB, and ltxD. The ltx operon appears to be present in all A. actinomycetemcomitans strains, but levels of toxin expression vary greatly among strains. Thus, to gain a better understanding of the expression and regulation of the ltx operon, we have analyzed the ltx promoters of a highly toxic (JP2) and a minimally toxic (652) strain of A. actinomycetemcomitans. The nucleotide sequence of the JP2 ltx promoter contains -10 and -35 elements situated 350 bases upstream of ltxC, and primer extension of JP2 RNA confirmed that they are functional in vivo. However, a second primer extension product of 40 bases was present, and analysis of a series of truncated JP2 promoters fused to lacZ suggested that the region immediately upstream of ltxC also promotes transcription in Escherichia coli. These results suggest that two promoters may direct ltx expression in JP2. In addition, a small open reading frame capable of encoding a peptide of 78 amino acids was identified upstream of ltxC. Northern blots showed that this open reading frame is transcribed as part of a 4.2-kb mRNA, a transcript not previously identified as being derived from the ltx operon. In contrast, strain 652 expresses low steady-state levels of ltx mRNA, and its intact ltx promoter was inefficient in transcribing lacZ in E. coli. The nucleotide sequence of the 652 promoter is similar to that of the JP2 promoter but contains a region of 530 bp that is not present in JP2. Of 15 additional strains of A. actinomycetemcomitans that were analyzed, 13 contained promoters resembling the 652 sequence and 2 possessed JP2-like promoters. Both strains possessing the JP2-like promoter expressed 10- to 20-fold-higher levels of leukotoxin than did the strains possessing promoters resembling the 652 promoter. These results suggest that high levels of leukotoxin expression may correlate with the presence of the JP2-like promoter.

Actinobacillus Infections

Human cathepsin O. Molecular cloning from a breast carcinoma, production of the active enzyme in Escherichia coli, and expression analysis in human tissues.

A cDNA encoding a novel member of the cysteine proteinase family of proteins has been cloned from a human breast carcinoma cDNA library, by using a polymerase chain reaction-based cloning strategy. The isolated cDNA contains an open reading frame coding for a polypeptide of 321 amino acids that has been tentatively called cathepsin O. This protein presents all the structural features characteristic of the different cysteine proteinases identified to date, including the active site cysteine residue that is involved in covalent intermediate formation during peptide hydrolysis. The cathepsin O cDNA was expressed in Escherichia coli, and after purification and refolding, the recombinant protein was able to degrade the synthetic peptides benzyloxycarbonyl-Phe-Arg-7-amido-4- methylcoumarin and benzyloxycarbonyl-Arg-Arg-7-amido-4-methylcoumarin widely used as substrates for cysteine proteinases. Cathepsin O proteolytic activity was abolished by trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), an inhibitor of this subclass of proteolytic enzymes, thus providing additional evidence that the isolated cDNA codes for an authentic cysteine proteinase. Northern blot analysis of poly(A)+ RNAs isolated from a variety of human tissues demonstrated that cathepsin O is expressed in all examined tissues, which is consistent with a putative role of this protein as a proteolytic enzyme involved in normal cellular protein degradation and turnover.

Amino Acid Sequence

Cloning and expression analysis of a novel human serine hydrolase with sequence similarity to prokaryotic enzymes involved in the degradation of aromatic compounds.

A full-length cDNA coding for a novel human serine hydrolase has been cloned from a breast carcinoma cDNA library. Nucleotide sequence analysis has shown that the isolated cDNA contains an open reading frame coding for a polypeptide of 274 amino acids and a complete Alu repetitive sequence within its 3'-untranslated region. The predicted amino acid sequence contains the Gly-X-Ser-X-Gly motif characteristic of serine hydrolases and displays extensive similarity to several prokaryotic hydrolases involved in the degradation of aromatic compounds. The highest degree of identities was detected with four serine hydrolases encoded by the bphD genes of different strains of Pseudomonas with the ability to degrade biphenyl derivatives. On the basis of these sequence similarities, this novel human enzyme has been tentatively called Biphenyl hydrolase-related protein (Bph-rp). The Bph-rp cDNA was expressed in Escherichia coli, and after purification, the recombinant protein was able to degrade p-nitrophenylbutyrate, a water-soluble substrate commonly used for assaying serine hydrolases. This hydrolytic activity was abolished by diisopropyl fluorophosphate, a covalent inhibitor of serine hydrolases, providing additional evidence that the isolated cDNA encodes a member of this protein superfamily. Northern blot analysis of poly(A)+ RNAs isolated from a variety of human tissues revealed that Bph-rp is mainly expressed in liver and kidney, which was also confirmed at the protein level by Western blot analysis with antibodies raised against purified recombinant Bph-rp. According to structural characteristics, hydrolytic activity and tissue distribution of Bph-rp, a potential role of this enzyme in detoxification processes is proposed.

Amino Acid Sequence