Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The organization of the metallothionein (MT) gene family has been demonstrated to be much more complex in humans than in the mouse, and possibly rodents in general. For humans, the MTs are encoded by a family of genes located at 16q13 representing 10 functional and 7 non-functional MT isoforms. In the present study, the 5' and 3' untranslated region sequences of the highly conserved, functional MT genes were utilized to generate primer pairs for the analysis of isoform-specific MT mRNA using reverse transcriptase-polymerase chain reaction (RT-PCR). Human kidneys from 13 weeks gestation through adulthood were examined for the expression of MT protein and mRNA. Immunohistochemical analysis demonstrated MT immunoreactivity to be confined exclusively to the proximal tubules of the adult and developing kidney. For all MT-positive cells, MT was localized in the cytoplasm and nuclear localization was variable. There was no correlation between nuclear staining and stage of development. Of the 10 MT genes examined (MT-1A, MT-1B, MT-1E, MT-1F, MT-1G, MT-1H, MT-1X, MT-2A, MT-3, and MT-4), mRNAs representing the MT-1E, MT-1F, MT-1X, and MT-2A genes were consistently expressed in all samples regardless of gestational age. There was no indication of a 'fetal form' of MT analogous to that noted to occur in human liver. Messenger RNA for the MT-1A gene was detected in 2 of 6 renal samples without correlation to gestational age. In no instance was mRNA for the MT-1B, MT-1G, MT-1H, MT-3 or MT-4 genes detected. These studies detail the initial determination of MT gene expression in the human renal system and provide the PCR primers for testing and determination of MT gene expression in other organ systems.
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PMID:Isoform-specific expression of metallothionein mRNA in the developing and adult human kidney. 861 55

In earlier studies of sporadic amyotrophic lateral sclerosis (ALS), a disease of unknown etiology, the amount of metallothioneins (MTs), a group of small (6-7 kDa) metal-binding proteins, appeared higher in liver, kidney and spinal cord from patients than from non-neurologic controls. Immunohistochemically, the expression of MT in the central nervous system appeared limited to glia. Since the highly conserved MTs isotypes share antigenic epitopes, they could not be distinguished by immunological methods. It thus proved necessary to estimate the expression of each individual MT messenger ribonucleic acid (mRNA) by performing reverse transcriptase polymerase chain reaction (RT-PCR)-mediated analysis of tissue samples. Tissues selected included liver, motor cortex and cervical cord at C6; MT mRNAs analyzed included MT1A, 1B, 1E, 1F, 1G, 2A, and 3. Also, special care was taken to avoid interference by amplification of the 6 MT pseudogenes. Except of MT3, already known as brain-specific, and MT1B which was not expressed in any tissue, mRNA levels of the other MT genes tended to be higher in ALS than in control liver samples, but the differences did not attain statistical significance. In the nervous system, the diverse MT genes were expressed over a greater range in ALS than in controls, but exhibited no change in a consistent direction. At the motor cortex, changes seemed to be less pronounced than at C6. MT3 was expressed in the motor cortex and the cord. The results provide no evidence for either the induction of a specific MT repertoire, or for the inability of glia to express any MT gene in ALS. Because the semi-quantitative RT-PCR technique does not permit detailed comparisons between the subtypes of MT expressed in the various tissues, the question whether a single inductor may be held responsible for the elevation of MT in the ALS liver and nervous system remains open. In conclusion, ALS tissue remains capable of expressing all the major MT genes. MT, present in protoplasmic glia, arises locally and is not secondary to increases of hepatic or renal MT. Because MT3 is also expressed by the normal and ALS spinal cord, it is a central nervous system-specific and not only a brain-specific protein. Thus, the excess of MT in ALS liver seems to be an effect of slower catabolism rather than faster synthesis of protein.
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PMID:Expression of different metallothionein messenger ribonucleic acids in motor cortex, spinal cord and liver from patients with amyotrophic lateral sclerosis. 890 18

The goals of this study were to determine the expression of metallothionein isoform 1 and 2 proteins (MT-1 and MT-2) in bladder cancer and then to determine which MT isoform-specific genes promoted the expression of these proteins. Immunohistochemical analysis disclosed no immunoreactivity for MT-1 and MT-2 (designated as MT-1/2 to reflect the nonspecificity of the antibody for the two isoforms) in cells comprising the normal bladder or in nonmalignant bladder disorders, such as cystitis and interstitial cystitis. Immunohistochemical analysis demonstrated that MT-1/2 was overexpressed in all samples of carcinoma in situ and in high-grade bladder cancer, with variable overexpression in low-grade bladder cancer and dysplastic lesions. The intensity and frequency of MT-1/2 staining correlated with the grade of the tumor. The MT-1 and MT-2 proteins are encoded by a family of eight genes (MT-1A, MT-1B, MT-1E, MT-1F, MT-1G, MT-IH, MT-1X, and MT-2A), and reverse transcriptase-polymerase chain reaction was used to determine which genes were expressed in the normal bladder and in bladder cancer. This analysis demonstrated that both normal and cancerous bladder tissue expressed mRNA for the MT-2A and MT-1X genes. The expression of MT-1E mRNA was variable in both normal bladder and bladder cancer specimens. Comparison of expression relative to that of beta-actin demonstrated that the level of MT-1X mRNA was overexpressed greatly in bladder cancer as compared to the level in normal bladder tissue. In contrast, the level of MT-2A mRNA was similar in both the normal and the bladder cancer specimens. The level of MT-1X expression did not vary with tumor grade. These studies suggest that the overexpression of MT-1/2 protein in bladder cancer is a result of the overexpression of the MT-1X gene.
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PMID:Metallothionein isoform 1 and 2 gene expression in the human bladder: evidence for upregulation of MT-1X mRNA in bladder cancer. 1127 Apr 23