Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.5.1.61 (porphobilinogen deaminase)
 637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Quantitation of target mRNAs using the reverse-transcription polymerase chain reaction found a widespread field of application in diverse biomedical diagnostic assays. However, the problem of varying sample quality has to be solved by correcting target molecule amounts through detection of an endogenous control template. The choice of an appropriate reference gene is still object of debate as pseudogene co-amplification and expression level variations may limit the usefulness of some currently used reference reactions. We compared quantitative expression levels of the commonly used endogenous reference genes beta-actin (beta-actin), beta-2-microglobulin (beta2-MG) and porphobilinogen deaminase (PBDG) using the TaqMan chemistry. With these assays we investigated the respective expression patterns in K562 cells and leucocytes of normal individuals as well as of malignoma patients. In K562 cells 1544+246 beta-actin, 65+30 beta2-MG and 22+/-8 PBDG copies/cell were detected. In normal leucocytes 491+/-97 beta-actin, 40+/-17 beta2-MG and <1 PBDG copies/cell were quantified. Leucocytes of various malignancies exhibited 84+/-51 beta-actin, 106+/-8 beta2-MG and <1 PBDG copies/cell. We conclude that beta2-MG is the most suitable reference gene tested as its variation between different sample origins and within distinct cell types was acceptable low.
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PMID:Quantitative analysis of beta-actin, beta-2-microglobulin and porphobilinogen deaminase mRNA and their comparison as control transcripts for RT-PCR. 1200 44

beta-Actin is often used as a housekeeping gene when performing reverse transcription-polymerase chain reaction (RT-PCR) analysis for cerebral ischemia models. In the present study, we tested two different control genes used for RT-PCR experiments, beta-actin and porphobilinogen deaminase (PBG-D), in a rat model of focal cerebral ischemia under normo- or hyperglycemic conditions. A three-vessel occlusion model with permanent middle cerebral artery occlusion was used in the rat. beta-Actin mRNA expression was decreased in hyperglycemic ischemic rats compared to normoglycemic ischemic animals 3 h post-ischemia. beta-Actin protein content was unchanged. As for PBG-D, its mRNA expression remained constant throughout the groups. Our data thus show that, following focal cerebral ischemia in hyperglycemic conditions, beta-actin is an unsuitable housekeeping gene whereas PBG-D is more appropriate. This study clearly demonstrates the importance of selecting a stable housekeeping gene when performing RT-PCR experiments.
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PMID:Decreased beta-actin mRNA expression in hyperglycemic focal cerebral ischemia in the rat. 1500 87

For interpretation of quantitative gene expression measurements in clinical tumor samples, a normalizer is necessary to correct expression data for differences in cellular input, RNA quality, and RT efficiency between samples. In many studies, a single housekeeping gene is used for normalization. However, no unequivocal single reference gene (with proven invariable expression between cells) has been identified yet. As the best alternative, the mean expression of multiple housekeeping genes can be used for normalization. In this study, no attempt was made to determine the gold-standard gene for normalization, but to identify the best single housekeeping gene that could accurately replace the measurement of multiple genes. Expression patterns of 13 frequently used housekeeping genes were determined in 80 normal and tumor samples from colorectal, breast, prostate, skin, and bladder tissues with real-time quantitative RT-PCR. These genes included, large ribosomal protein, beta-actin, cyclophilin A, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerokinase 1, beta-2-microglobin, beta-glucuronidase, hypoxanthine ribosyltransferase (HPRT), TATA-box-binding protein, transferrin receptor, porphobilinogen deaminase, ATP synthase 6, and 18S ribosomal RNA. Principal component analysis was used to analyze these expression patterns, independent of the level of expression. Our approach identified HPRT as the single best reference gene that could be used as an accurate and economic alternative for the measurement of multiple housekeeping genes. We recommend this gene for future studies to standardize gene expression measurements in cancer research and tumor diagnostics until a definite gold standard has been determined.
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PMID:Normalization of gene expression measurements in tumor tissues: comparison of 13 endogenous control genes. 1554 3

Quantitative polymerase chain reaction (Q-PCR) studies of urine sediments have demonstrated an increased expression of cytotoxin genes during episodes of acute rejection of renal allografts. To compensate for differences in initial sample size and cDNA preparation, standard Q-PCR experiments involve normalization to a reference gene. Although stable expression of reference genes is a prerequisite for any Q-PCR analysis, commonly used reference genes have demonstrated a varying expression across tissues and various stimuli. In this study, cellular expression of several reference genes was investigated in a mixed lymphocyte reaction as a model of gene expression during alloreactive T-lymphocyte activation and acute rejection. Gene expression was quantified using Q-PCR, normalized to cell counts obtained by DNA quantification and corrected for cell polyploidy using flow cytometry. Examined reference genes were 18S rRNA, beta-actin (ACTB), hydroxymethylbilane synthase (HMBS), hypoxanthine phosphoribosyltransferase (HPRT1) and peptidylprolyle isomerase B (PPIB). This study also examined two novel T-lymphocyte-specific reference genes: CD3E and CD8B. HMBS and HPRT were 18.8- and 7.4-fold upregulated, respectively, ACTB was 5.3-fold upregulated, PPIB was 3.2-fold upregulated while 18S rRNA remained stably expressed. The T-lymphocyte-specific reference gene CD3E remained stable while CD8B was upregulated 2.3-fold. In conclusion, several commonly used reference genes were actively regulated during alloreactive T-lymphocyte activation. Additionally, we introduce two stable T-lymphocyte-specific reference genes that might be useful in a Q-PCR analysis of T-lymphocyte-specific cytotoxin genes in urine sediments, as they overcome the contribution of reference gene mRNA from cells irrelevant for diagnosis.
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PMID:Commonly used reference genes are actively regulated in in vitro stimulated lymphocytes. 1725 26

Quantitative measurements of gene expression require correction for tissue sample size, RNA quantity, and reverse transcription efficiency. This can be achieved by normalization with control genes. The study was designed to identify candidates not altered after brain trauma. Male C57Bl/6 mice were anesthetized with isoflurane, and a pneumatic brain trauma was induced by controlled cortical impact (CCI) on the right parietal cortex. Brains were removed at 15 min, and 3, 6, 12 and 24 h after CCI and from naive animals (n = 6 each). Absolute copies of six control genes (beta-2-microglobin [B2M], cyclophilin A, beta-actin, hypoxanthine ribosyltransferase [HPRT], porphobilinogen deaminase [PBGD], and glyceraldehyde-3-phosphate dehydrogenase [GAPDH]) and one example target gene (iNOS) were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR; Lightcycler) in the traumatic focus and contralateral tissue. Control gene expression was stable until 12 h after CCI. At 24 h after CCI expression of B2M, cyclophilin A and HPRT remained stable in the contusion, while expression of beta-actin, GAPDH, and PBGD increased. Due to variations between animals (+/-85%), increases in beta-actin (+64%) and GAPDH (+59%) did not reach the level of significance. In non-contused tissue, expression of all genes dropped 24 h after CCI (range, -17% to -61%). Due to low variations between animals and stable expression after CCI, B2M and cyclophilin A seem to be suitable to serve as single normalizer. Normalization of the example target gene iNOS resulted in varying relative expression extending from onefold (PBDG) to 10-fold (HPRT). The results suggest that the knowledge of the temporal profile of control genes is essential to properly interpret results of mRNA quantification.
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PMID:Selection of endogenous control genes for normalization of gene expression analysis after experimental brain trauma in mice. 1862 56