Sequence of variant and mutant GM-CSF receptor α subunits

. The α-1 and α-2 isoforms are natural splicing variants of the α subunit. They differ completely from their C-terminal amino acids (italics). The GM5 chimeric α subunit consists of sequences from the proximal proline-rich domain of the GM-CSF receptor α subunit (bold) fused to distal sequences from the human IL-5 α subunit (underlined). The term-3 mutant α subunit lacks the C-terminal amino acids because of placement of a stop codon after the codons for 34 intracellular amino acids. The term-1 mutant α subunit has only 5 intracellular amino acids.