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Department of Cellular and Structural
Biology, University of Texas Health Science Center at San
Antonio, 78229, San Antonio, TX, USA.
In the present study, we generated transgenic
mice that overexpress catalase or CuZn superoxide dismutase
(CuZnSOD) in all tissues using large genomic DNA fragments.
An 80 kb human genomic DNA, containing the 33 kb human CAT
gene as well as the 41 kb of 5' and the 6 kb of 3' flanking
regions, was obtained by screening a human P1 library and
was used to produce transgenic mice Tg(CAT). Transgenic mice
Tg(SOD1) were produced by a similar strategy using a 64 kb
human genomic DNA containing the 10 kb human SOD1 gene and
the 27 kb of both 5' and 3' flanking regions. Catalase mRNA
levels were 2-6- fold higher and catalase activity levels
were 2-4- fold higher in the various tissues of the hemizygous
Tg(CAT) mice compared with wild type mice. The mRNA levels
for CuZnSOD were 2-12- fold higher and the CuZnSOD activity
levels were 2-5- fold higher in the hemizygous Tg(SOD1) mice
compared with wild type mice. In summary, our study demonstrates
that a strategy of using large genomic DNA containing either
the entire human CAT or SOD1 gene with large flanking regions
gives ubiquitous increased _expression of CuZnSOD and catalase.
In addition, the _expression of catalase closely reflects
the tissue specific pattern found in the endogenous gene.
These transgenic mice will be useful in studying the role
of oxidative stress/damage in aging and age-related pathologies.
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Department of Pediatrics, University
of California, San Francisco 94143-0546, USA.
Oxidative damage has been implicated
in the aging process and in a number of degenerative diseases.
To investigate the role of oxygen radicals in the aging
process in mammals, the life spans of transgenic mice on
a CD-1 background expressing increased levels of CuZn superoxide
dismutase (CuZnSOD), the enzyme that metabolizes superoxide
radicals, were determined. Homozygous transgenic mice with
a two- to five-fold elevation of CuZnSOD in various tissues
showed a slight reduction of life span, whereas hemizygous
mice with a 15- to 3-fold increase of CuZnSOD showed no
difference in life span from that of the nontransgenic littermate
controls. The results suggest that constitutive and ubiquitous
overexpression of CuZnSOD alone is not sufficient to extend
the life spans of transgenic mice.
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St. Jude Children's Research Hospital,
332 North Lauderdale Drive, Memphis, TN 38105, USA.
The hematologic disorders of beta-thalassemia
and sickle cell disease are the most prevalent of human
genetic diseases. Although palliative therapies and curative
stem cell transplantation therapy have been developed for
these disorders, treatment still remains suboptimal and
many patients suffer significant morbidity and early mortality.
Therefore, development of a gene therapy approach has been
sought for many years. Major progress in the globin gene
therapy field has been achieved by several laboratories.
Using lentiviral vectors to obtain high-level _expression
of complex globin gene cassettes, therapeutic correction
of several murine models of beta-thalassemia, and sickle
cell disease was recently reported. This progress, coupled
with developments in the ability to select and expand genetically
modified stem cells in vivo, has advanced the possibility
of gene therapy for the hemoglobin disorders in the near
future. We review the developments in several areas that
are critical for successful gene therapy of the hemoglobin
disorders.
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