Publication Date:
2008-11-16
Description:
Signal transducer and activator of transcription 3 (Stat3) is a key signaling intermediate that is activated by several cytokines that regulate hematopoiesis, including granulocyte-colony stimulating factor (G-CSF), interleukin 6, and stem cell factor (SCF). Studies using mice with Stat3 deletion targeted to hematopoietic cells have shown that Stat3 negatively regulates basal granulopoiesis but positively regulates emergency granulopoiesis. Stat3 also has been reported to promote B lymphocyte differentiation. Defining the hematopoietic functions of Stat3 is further complicated by the existence of two isoforms: full-length Stat3α (p92), and truncated Stat3β (p83). Stat3β is derived from alternative mRNA splicing resulting in replacement of the C-terminal transactivation domain with 7 unique amino acids (CT7), which have been demonstrated to confer markedly prolonged nuclear retention. Homozygous Stat3α-deficient mice are not viable, whereas Stat3β-deficient mice survive to adulthood and are fertile, but have increased inflammatory responses compared to wild-type mice. We compared basal granulopoiesis and lymphopoiesis, as well as emergency granulopoiesis, in homozygous Stat3β-deficient mice (βΔ/βΔ), which express only Stat3α, vs. their wild-type (+/+) littermates. We found that βΔ/βΔ mice were significantly leukopenic (2880 ± 1260/ml v. 4600 ± 1670/ml; p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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