Post-transcriptional regulation of chymase expression in mast cells. A cytokine-dependent mechanism for controlling the expression of granule neutral proteases of hematopoietic cells.
Although all mouse mast cells are derived from a common progenitor, these effector cells exhibit tissue-specific differences in their expression of the chymase family of serine proteases whose genes reside on chromosome 14. Immature bone marrow-derived mast cells (mBMMC), developed in vitro with interleukin (IL) 3-enriched medium, were cultured in the presence or absence of IL-10 to determine at the molecular level how the expression of the individual chymases is differentially regulated. As assessed by RNA blot analysis, mBMMC contain high steady-state levels of the transcript that encodes mouse mast cell protease (mMCP) 5, but not the homologous chymase transcripts that encode mMCP-1, mMCP-2, or mMCP-4. Nevertheless, nuclear run-on analysis revealed that these cells transcribe all four mast cell chymase genes. IL-10 elicited high steady-state levels of the mMCP-2 transcript, and pulse-chase experiments revealed that the half-life of the mMCP-2 transcript in mBMMC maintained in the presence of IL-10 is approximately 4-fold longer than that in replicate cells subsequently cultured in medium without IL-10. Reverse transcription-polymerase chain reaction/nucleotide sequence analysis demonstrated that mBMMC cultured in the absence or presence of IL-10 correctly process mMCP-2 pre-mRNA. Experiments with cycloheximide and actinomycin D indicated that IL-10 induces expression of a trans-acting factor(s) that stabilizes the mMCP-2 transcript or facilitates its processing. The discovery that the expression of certain chymases in mBMMC is regulated primarily at the post-transcriptional level provides a basis for understanding the mechanism by which specific cytokines dictate expression of the chromosome 14 family of serine proteases in cells that participate in inflammatory processes.
Xia
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Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
Ghildyal
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N
Austen
K F
KF
Stevens
R L
RL
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D053818:Chymases; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D016753:Interleukin-10 / Q000502:physiology*; D008407:Mast Cells / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics*; D014158:Transcription, Genetic
D017931:DNA Primers; D012333:RNA, Messenger; D016753:Interleukin-10; D012697:Serine Endopeptidases; D053818:Chymases