1: Blood. 2005 Oct 1;106(7):2530-3. Epub 2005 Jun 2. 

Recurrent retroviral vector integration at the Mds1/Evi1 locus in nonhuman
primate hematopoietic cells.

Calmels B, Ferguson C, Laukkanen MO, Adler R, Faulhaber M, Kim HJ, Sellers S,
Hematti P, Schmidt M, von Kalle C, Akagi K, Donahue RE, Dunbar CE.

Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD, USA.

Recent reports linking insertional activation of LMO2 following gene therapy for
X-linked severe combined immunodeficiency (X-SCID) have led to a re-evaluation
of risks following gene therapy with retroviral vectors. In our analysis of 702
integration sites in rhesus macaques that underwent transplantation up to 7
years earlier with autologous CD34+ cells transduced with amphotropic murine
leukemia virus (MLV)-derived retroviral vectors containing marker genes, we
detected insertion into one locus, the Mds1/Evi1 region, a total of 14 times in
9 animals. Mds1/Evi1 integrations were observed stably long term, primarily in
myeloid cells. We hypothesize that this over-representation likely results from
an impact on the self-renewal and engraftment potential of CD34+ progenitor
cells via insertional mutagenesis at this specific locus. There is no evidence
of ongoing in vivo clonal expansion of the Mds1/Evi1 populations, and all
animals are hematologically normal without evidence for leukemia.
Characterization of integration sites in this relevant preclinical model
provides critical information for gene therapy risk assessment as well as
identification of genes controlling hematopoiesis.

PMID: 15933056 [PubMed - in process]


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2: Blood. 2005 Sep 15;106(6):2147-55. Epub 2005 May 24. 

Dysplastic definitive hematopoiesis in AML1/EVI1 knock-in embryos.

Maki K, Yamagata T, Asai T, Yamazaki I, Oda H, Hirai H, Mitani K.

Department of Hematology, Dokkyo University School of Medicine, 880
Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan.

The AML1/EVI1 chimeric gene is created by the t(3;21)(q26;q22) chromosomal
translocation seen in patients with leukemic transformation of myelodysplastic
syndrome or blastic crisis of chronic myelogenous leukemia. We knocked-in the
AML1/EVI1 chimeric gene into mouse Aml1 genomic locus to explore its effect in
developmental hematopoiesis in vivo. AML1/EVI1/+ embryo showed defective
hematopoiesis in the fetal liver and died around embryonic day 13.5 (E13.5) as a
result of hemorrhage in the central nervous system. The peripheral blood had
yolk-sac-derived nucleated erythroblasts but lacked erythrocytes of the
definitive origin. Although E12.5 fetal liver contained progenitors for
macrophage only, E13.5 fetal liver contained multilineage progenitors capable of
differentiating into dysplastic myelocyte and megakaryocyte. No erythroid
progenitor was detected in E12.5 or E13.5 fetal liver. Hematopoietic progenitors
from E13.5 AML1/EVI1/+ fetal liver were highly capable of self-renewal compared
with those from wild-type liver. Maintained expression of PU.1 gene and
decreased expression of LMO2 and SCL genes may explain the aberrant
hematopoiesis in AML1/EVI1/+ fetal liver.

PMID: 15914564 [PubMed - indexed for MEDLINE]


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