Placental Defects and Embryonic Lethality in Mice Lacking Suppressor of Cytokine Signaling 3
Placental defects and embryonic lethality in mice lacking suppressor of cytokine signaling 3 Andrew W. Roberts*, Lorraine Robb*, Steven Rakar†, Lynne Hartley*, Leonie Cluse*, Nicos A. Nicola*, Donald Metcalf*, Douglas J. Hilton*, and Warren S. Alexander*‡ *The Walter and Eliza Hall Institute of Medical Research and Cooperative Research Centre for Cellular Growth Factors, Post Office, Royal Melbourne Hospital, Victoria 3050, Australia; and †AMRAD Operations Pty. Ltd., Richmond, Victoria 3121, Australia Contributed by Donald Metcalf, May 31, 2001 Mice lacking suppressor of cytokine signaling 3 (SOCS3) exhibited activity of which it ultimately inhibits. SOCS proteins may also embryonic lethality with death occurring between days 11 and 13 target associated signaling molecules for degradation. The SOCS ,of gestation. At this stage, SOCS3؊/؊ embryos were slightly smaller box domain has been shown to interact with elongins B and C than wild type but appeared otherwise normal, and histological proteins involved in the cellular ubiquitination machinery that analysis failed to detect any anatomical abnormalities responsible targets proteins for destruction via the proteasome (9, 10). Thus, for the lethal phenotype. Rather, in all SOCS3؊/؊ embryos exam- SOCS proteins may regulate cytokine responses through control ined, defects were evident in placental development that would of the turnover of signaling proteins as well as directly inhibiting account for their developmental arrest and death. The placental their catalytic activity or recruitment to the signaling complex. spongiotrophoblast layer was significantly reduced and accompa- The physiological significance of SOCS-mediated control of nied by increased numbers of giant trophoblast cells. Delayed cytokine signaling has emerged from studies in which these branching of the chorioallantois was evident, and, although em- regulators have been functionally deleted in mice.
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