RNAse protection analysis of the GMRβ chain using total RNA from hematopoietic cell lines (TF-1), primary myeloid cells (purified neutrophils, CD34⁺ cells, and mononuclear cells from normal bone marrow), and leukemic blasts from patients with AML. The full-length probe of 248 bp protected a fragment of 191 bp from nucleotides 1429 to 1620 of the published β_C chain sequence17 and 64 bp for the β_IT chain.