Identification of an additional isoform of STAT5 expressed in immature macrophages
Lokuta, M.A.; McDowell, M.A.; Paulnock, D.M.
Journal of Immunology 161(4): 1594-1597
1998
ISSN/ISBN: 0022-1767 PMID: 9712020 Document Number: 494397
We are interested in understanding the molecular basis of macrophage (Mphi) differentiation and activation by cytokines. Recent reports have suggested that the transcription factor STAT5 may play a role in Mphi differentiation. In the experiments described here, we assessed the expression of STAT5-related molecules in three Mphi cell lines, RAW 264.7, WEHI-3, and WEHI-3D+, which represent different stages of Mphi maturation, and also in primary peritoneal and bone marrow Mphi from BALB/c mice. The studies revealed that the previously characterized STAT5a and STAT5b isoforms are detectable at both the mRNA and protein levels in these Mphi populations. Additional STAT5-related proteins were detected by immunoblot analysis and were preferentially expressed in both the immature WEHI-3 cell population and the adherent bone marrow population containing immature Mphi. These results identify new isoforms of STAT5 and demonstrate that distinct patterns of expression of STAT5-related proteins are observed in Mphi at different stages of maturation.