Molecular cloning and analysis of functional cDNA and genomic clones encoding bovine cellular retinoic acid-binding protein.

Shubeita, Huda E.; Sambrook, Joseph; McCormick, Anne M.

doi:10.1073/pnas.84.16.5645

Cited by 110 publications

(44 citation statements)

References 56 publications

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“…Table 1 contains a list of agents and conditions that did not affect GT expression significantly (<50%) in isolated rat hepatocytes. These results suggest that GT expression in hepatocytes is not due to growth factors or hormones that (i) are usually present in serum (e.g., platelet-derived growth factor, (ii) are normally added to hepatocyte culture medium [e.g., insulin, corticosteroids, triiodothyronine, epidermal growth factor (35) acid-binding protein (38) has been detected in significant amount in liver.…”

Section: Expression Of Gt and Gt-related Transcripts In Normalmentioning

confidence: 76%

Evidence for expression of the facilitated glucose transporter in rat hepatocytes.

Rhoads

Takano

Gattoni‐Celli

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

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The eukaryotic facilitated glucose transporter (GT) is expressed by many cell types, with the notable exception of hepatocytes; however, GT is expressed by several hepatoma cell lines, including the well-differentiated lines Fao, Hep3B, and HepG2. We report on studies carried out to determine the aspect(s) of the transformed phenotype that might be responsible for activating GT expression. Using RNA blot analysis with probes derived from rat GT cDNA, we found that GT was expressed by rat hepatocytes under two conditions (i) in vitro, when isolated hepatocytes were placed in cell culture, and (a) in vivo, when rats were subjected to starvation for .2 days. However, GT expression was not an obligatory feature of hepatomas, since two primary hepatocellular carcinomas did not express any GT mRNA. GT expression in hepatocytes was reduced by addition of dimethyl sulfoxide or sodium butyrate to the culture medium. Since these reagents are known to promote differentiation in some cell culture systems, their effect on hepatocytes may be to maintain the GT repression normally observed in vivo. Inclusion or exclusion in the culture medium of several other agents that enhance hepatocyte viability (serum, insulin, corticosteroids, epidermal growth factor, or triiodothyronine) did not affect GT expression. It is unclear whether the two conditions that led to GT expression in hepatocytes are related by a common signaling mechanism. Possibly, both cases involve a "stress" response: in vivo, a normal physiological response to starvation; in vitro, a response to a major alteration in the cellular environment.

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Section: Expression Of Gt and Gt-related Transcripts In Normalmentioning

confidence: 76%

Evidence for expression of the facilitated glucose transporter in rat hepatocytes.

Rhoads

Takano

Gattoni‐Celli

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

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“…A variety of deletion mutants of S. mutans was constructed as described in detail elsewhere (23,24). Briefly, fragments flanking the gene of interest were amplified with gene-specific primers carrying a BamHI recognition site.…”

Section: Methodsmentioning

confidence: 99%

Genetics and Physiology of Acetate Metabolism by the Pta-Ack Pathway of Streptococcus mutans

Kim

Ahn

Burne

2015

Appl Environ Microbiol

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In the dental caries pathogen Streptococcus mutans, phosphotransacetylase (Pta) catalyzes the conversion of acetyl coenzyme A (acetyl-CoA) to acetyl phosphate (AcP), which can be converted to acetate by acetate kinase (Ack), with the concomitant generation of ATP. A ⌬ackA mutant displayed enhanced accumulation of AcP under aerobic conditions, whereas little or no AcP was observed in the ⌬pta or ⌬pta ⌬ackA mutant. The ⌬pta and ⌬pta ⌬ackA mutants also had diminished ATP pools compared to the size of the ATP pool for the parental or ⌬ackA strain. Surprisingly, when exposed to oxidative stress, the ⌬pta ⌬ackA strain appeared to regain the capacity to produce AcP, with a concurrent increase in the size of the ATP pool compared to that for the parental strain. The ⌬ackA and ⌬pta ⌬ackA mutants exhibited enhanced (p)ppGpp accumulation, whereas the strain lacking Pta produced less (p)ppGpp than the wild-type strain. The ⌬ackA and ⌬pta ⌬ackA mutants displayed global changes in gene expression, as assessed by microarrays. All strains lacking Pta, which had defects in AcP production under aerobic conditions, were impaired in their abilities to form biofilms when glucose was the growth carbohydrate. Collectively, these data demonstrate the complex regulation of the Pta-Ack pathway and critical roles for these enzymes in processes that appear to be essential for the persistence and pathogenesis of S. mutans. Streptococcus mutans is a facultatively anaerobic, Gram-positive bacterium with fermentative metabolism. Human dental caries is associated with increased proportions of multiple acid-tolerant species in tooth biofilms, but S. mutans shows a particularly strong association with the initiation and progression of this common infectious disease (1, 2). The pathogenic potential of S. mutans is highly dependent on its ability to form biofilms, to use a variety of carbohydrates to produce organic acids that dissolve tooth mineral, and to tolerate stresses commonly encountered in oral biofilms. In particular, tolerance of a variety of reactive oxygen species (ROS), including superoxide ions and hydrogen peroxide, is considered critical for S. mutans to overcome antagonism by oral commensals and host defenses (3, 4).S. mutans has a partial tricarboxylic acid (TCA) cycle and lacks cytochromes, so the primary route for ATP generation by this organism is through the Embden-Meyerhof-Parnas pathway (4-7). Under anaerobic conditions and with growth in the presence of an excess of a preferred carbohydrate, the pyruvate generated by glycolysis is acted on by lactate dehydrogenase (LDH), which is allosterically activated by fructose-1,6-bisphosphate (F-1,6-BP), to produce lactate and regenerate NAD (4, 8). If carbohydrate is limiting, S. mutans produces a pyruvate formate lyase enzyme, which converts pyruvate to acetyl coenzyme A (acetyl-CoA) and formate (Fig. 1). However, the pyruvate formate lyase (PFL) enzyme of S. mutans is inactivated by oxygen, so under aerobic conditions and if catabolite repression is alleviated (M. Watts and R. A....

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“…Construction of mutant strains. Deletion mutants of S. mutans were constructed as previously described (33,34). Briefly, using primers flanking the gene of interest, two flanking sequences that incorporated restriction enzyme sites for BamHI for the upstream and downstream fragments were amplified.…”

Section: Methodsmentioning

confidence: 99%

Core-Gene-Encoded Peptide Regulating Virulence-Associated Traits in Streptococcus mutans

2013

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bRecently, high-coverage genome sequence of 57 isolates of Streptococcus mutans, the primary etiological agent of human dental caries, was completed. The SMU.1147 gene, encoding a 61-amino-acid (61-aa) peptide, was present in all sequenced strains of S. mutans but absent in all bacteria in current databases. Reverse transcription-PCR revealed that SMU.1147 is cotranscribed with scnK and scnR, which encode the histidine kinase and response regulator, respectively, of a two-component system (TCS). The C terminus of the SMU.1147 gene product was tagged with a FLAG epitope and shown to be expressed in S. mutans by Western blotting with an anti-FLAG antibody. A nonpolar mutant of SMU.1147 formed less biofilm in glucose-containing medium and grew slower than did the wild-type strain under aerobic and anaerobic conditions, at low pH, or in the presence of H 2 O 2 . Mutation of SMU.1147 dramatically reduced genetic competence and expression of comX and comY, compared to S. mutans UA159. The competence defect of the SMU.1147 mutant could not be overcome by addition of sigX-inducing peptide (XIP) in defined medium or by competence-stimulating peptide (CSP) in complex medium. Complementation with SMU.1147 on a plasmid restored all phenotypes. Interestingly, mutants lacking either one of the TCS components and a mutant lacking all three genes behaved like the wild-type strain for all phenotypes mentioned above, but all mutant strains grew slower than UA159 in medium supplemented with 0.3 M NaCl. Thus, the SMU.1147-encoded peptide affects virulence-related traits and dominantly controls quorum-sensing pathways for development of genetic competence in S. mutans.

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Molecular cloning and analysis of functional cDNA and genomic clones encoding bovine cellular retinoic acid-binding protein.

Abstract: A recombinant cDNA clone, pCRABP-

Cited by 110 publications

References 56 publications

Evidence for expression of the facilitated glucose transporter in rat hepatocytes.

Evidence for expression of the facilitated glucose transporter in rat hepatocytes.

Genetics and Physiology of Acetate Metabolism by the Pta-Ack Pathway of Streptococcus mutans

Core-Gene-Encoded Peptide Regulating Virulence-Associated Traits in Streptococcus mutans

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