Impaired interleukin-3 (IL-3) response of the A/J mouse is caused by a branch point deletion in the IL-3 receptor alpha subunit gene.
Interleukin-3 (IL-3) alone does not support hematopoietic colony formation of bone marrow cells from the A/J mouse. To elucidate the molecular lesion in A/J mice, we examined expression of the alpha and beta subunits of the IL-3 receptor (IL-3R). While IL-3R beta was normally expressed, IL-3R alpha was not detectable on the surface of A/J-derived cells by antibody staining. Genetic linkage analysis using recombinant inbred mouse strains between A/J and IL-3-responsive C57BL/6 indicated that the IL-3R alpha gene locus was responsible for the impaired IL-3 response in A/J mice. Molecular cloning and characterization of A/J-derived IL-3R alpha cDNA revealed that it lacked the sequence corresponding to exon 8, which encodes 10 amino acid residues in the extracellular domain. The aberrant splicing was due to a 5 base pair deletion at the branch point in intron 7 and was reproduced in heterologous cells by transfecting with an IL-3R alpha minigene carrying the deleterious intron. The A/J-specific abnormal form of IL-3R alpha was localized inside the cells, but not on the cell surface, providing the molecular basis for the impaired IL-3 response in the A/J mouse.
Ichihara
M
M
Department of Cell Biology, DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, CA 94304.
Hara
T
T
Takagi
M
M
Cho
L C
LC
Gorman
D M
DM
Miyajima
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D015870:Gene Expression; D008040:Genetic Linkage; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007377:Interleukin-3 / Q000494:pharmacology / Q000502:physiology*; D007438:Introns / Q000235:genetics; D051379:Mice; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D016185:Receptors, Interleukin-3 / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D017384:Sequence Deletion / Q000235:genetics*
D018076:DNA, Complementary; D007377:Interleukin-3; D012333:RNA, Messenger; D016185:Receptors, Interleukin-3