Effects of point mutation C -> T at-64 of human delta globin gene promoteron DNA binding proteins

By electrophoretic mobility shift assay (EMSA), the effect of point mutatio n C-->T at - 64 of human F-globin gene on its binding proteins has been stu died, Two segments of 36 bp from - 83- - 48 bp of the delta globin gene pro moter, named WOG and MOG, were synthesized, WOG includes wild type CAAT-lik e box (CCAAC), while MOG includes the mutant CAAT-like box (CCAAT, - 64 C-- >T). Results indicate that: (i) in erythroid cell lines MEL, K562 and Hemin induced K562, the affinity of MOG with CCAAT binding protein (CBF) and GAT A-1 was greatly increased; (ii) in Hemin induced K562 cell line, there were another two novel specific DNA binding proteins, named C and D temporarily , besides the above two factors. The former was combined with WOG and MOG, likely indicating its relation with the increased gene expression after ind uction. The latter was only combined with MOG, which had possible relations hip with the point mutation of - 64 C-->T; (iii) EN1SA also indicates that the suppression mechanisms of the expression of delta globin gene is differ ent in various periods of human developments, The result evidently supports the hypothesis that the defect CAAT-like box in human delta globin gene co ntributes the main reason of its low level expression, The defect cis-actin g element CAAT-like box affects gene expression by its combination with the trans-acting element CBF and GATA-1.