Generation of a variant of human interleukin-4 by alternative splicing.
A second species of interleukin-4 (IL-4) mRNA was identified using both a reverse transcription-polymerase chain reaction and an RNase protection assay. This novel IL-4 mRNA was 48 base pairs smaller than IL-4 mRNA, which is the size of IL-4 exon 2. Sequence data of cloned cDNA demonstrated that this variant contained IL-4 exons 1,3 and 4, with exon 1 spliced directly to exon 3 in an open reading frame. The entire protein encoding region of this variant, named IL-4 delta 2, was identical to IL-4 except for the omission of exon 2. IL-4 delta 2 mRNA was detected in all human peripheral blood mononuclear cells tested and in purified CD3+ T cells. Amounts of both IL-4 and IL-4 delta 2 mRNAs increased upon T cell activation, although IL-4 mRNA increased to a greater extent than IL-4 delta 2 mRNA did. Human IL-3, IL-5, IL-13, and granulocyte macrophage-colony stimulating factor did not use alternative splicing to delete exon 2. We speculate that IL-4 delta 2 may regulate IL-4 function.
Alms
W J
WJ
Department of Microbiology and Immunology, University of Maryland, Baltimore 21201, USA.
Atamas
S P
SP
Yurovsky
V V
VV
White
B
B
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D005091:Exons; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics; D015847:Interleukin-4 / Q000235:genetics*; D015848:Interleukin-5 / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D012260:Ribonucleases / Q000494:pharmacology; D013601:T-Lymphocytes / Q000378:metabolism
D007377:Interleukin-3; D015848:Interleukin-5; D012333:RNA, Messenger; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D012260:Ribonucleases