Interleukin-5 does not influence differential transcription of transmembrane and soluble isoforms of IL-5R alpha in vivo.
Interleukin-5 (IL-5) promotes signal transduction and expansion of eosinophil colonies in bone marrow via interactions with its heterodimeric receptor (IL-5R). Two variants encoding soluble forms of the alpha subunit (sIL-5R alpha) have been described, although the signals promoting and/or limiting differential transcription remain to be clarified.


OBJECTIVE
Our intent was to explore the role of IL-5 in regulating differential transcription of these splice variants in vivo.


METHODS
We have designed a quantitative reverse transcriptase-polymerase chain reaction assay to detect transcripts encoding the transmembrane, soluble 1 and 2 forms of IL-5R alpha in two strains of wild-type (BALB/c and C57BL/6) and corresponding IL-5 gene-deleted mice. Wild-type mice respond to S. mansoni infection with a gradual increase in serum IL-5 and eosinophilia, which is not observed in IL-5 gene-deleted mice.


CONCLUSIONS
We find that IL-5 is not necessary for differential splicing to occur in vivo, as all three forms of the IL-5R alpha are detected in both strains of IL-5 gene-deleted mice, with ratios of transcript expression (transmembrane : soluble 1 : soluble 2) that were indistinguishable from their wild-type counterparts. Differential splicing does vary markedly between strains, potentially because of local effects of strain-specific polymorphisms.
Byström
Jonas
J
Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1883, USA.
Dyer
Kimberly D
KD
Ting-De Ravin
Suk See
SS
Naumann
Nora
N
Stephany
David A
DA
Foster
Paul S
PS
Wynn
Thomas A
TA
Rosenberg
Helene F
HF
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001853:Bone Marrow / Q000473:pathology; D018076:DNA, Complementary / Q000235:genetics; D004804:Eosinophils / Q000473:pathology; D005091:Exons; D015848:Interleukin-5 / Q000097:blood / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics; D018123:Receptors, Interleukin / Q000096:biosynthesis* / Q000235:genetics*; D053649:Receptors, Interleukin-5; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012555:Schistosomiasis mansoni / Q000235:genetics / Q000276:immunology / Q000473:pathology; D012995:Solubility; D013045:Species Specificity; D014158:Transcription, Genetic
D018076:DNA, Complementary; D015848:Interleukin-5; D020033:Protein Isoforms; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5