DIFFERENTIAL EXPRESSION OF A BASIC HELIX-LOOP-HELIX PHOSPHOPROTEIN GENE, G0S8, IN ACUTE-LEUKEMIA AND LOCALIZATION TO HUMAN-CHROMOSOME 1Q31

A basic helix-loop-helix phosphoprotein gene, G0S8, was recently isola ted by differential screening of cDNA from human blood mononuclear cel ls stimulated with a T cell mitogen and cycloheximide. In this study, G0S8 expression was examined in normal and malignant hematopoietic cel ls by Northern blot analysis and reverse transcription-polymerase chai n reaction (RT-PCR). G0S8 expression was observed in most fresh sample s of acute myelogenous leukemia (AML) (28/30) and most cases of adult acute lymphoblastic leukemia (ALL) (9/11) regardless of clinical class ification. G0S8 mRNA was also detected in all cases tested of chronic myelogenous leukemia (CML) in blast crisis. However, G0S8 expression w as not defected in CML patients in chronic phase, nor in normal bone m arrow or other hematopoietic cells. G0S8 has been mapped using fluores cence in situ hybridization (FISH) to human chromosome 1q31, the same site reported for the B cell homolog BL34/1R20 and within a region imp licated in the development of hematological malignancies. The consiste nt observation of G0S8 mRNA in patient samples of acute leukemia sugge sts that G0S8 expression may either play a role in leukemogenesis or r epresent a common consequence of dysregulated growth.