Transient expression assay of [A]gamma-588 [A/G] mutations in the k562 cell line

In the previous study, we have shown that the presence of A allele at position -588 in [A]gamma -globin gene was highly frequent and closely associated with fetal hemoglobin elevation among beta-thalassemia intermedia patients. Therefore, we decided to investigate whether this allele [A allele at -588] could result in an increase in [A]gamma-globin gene expression to ameliorate the severity of the disease in thalassemia patients. Three constructs containing ji locus control region, [A]gamma -globin and beta-globin genes were designed and employed in the transient expression assay. The difference among constructs was in the promoter region of, [A]gamma -globin gene [A and G alleles at -588]. A construct with T to C base substitution at -175 of, [A]gamma -globin, created by site-directed mutagenesis, was selected as positive control. The K562 cell line was transfected with the above constructs. Subsequently, the expression of, [A]gamma -globin gene was determined by quantitative real-time reverse transcription-PCR. There was not a significant increase in the expression of, [A]gamma -globin gene in the construct containing A allele comparing the one with G allele at -588. -588 [A>G] mutation does not play a major role in regulation of, [A]gamma -globin gene, suggesting that other factors may be involved

Stimulation of the absorption of macromolecules in Giardia lamblia infected mice intestine.

The absorption of 125I-labelled bovine serum albumin, gamma-globulin and alpha-lactalbumin was considerably enhanced in G. lamblia infected Swiss mice intestine compared to uninfected controls. The binding of 125I-proteins to brush border membrane was however, significantly (P less than 0.01) low in infected animals. Kinetic studies with gamma-globulin binding to brush borders revealed a decrease in the number of binding sites in infected animals (1.52) compared to controls (2.86 micrograms/mg protein) with no change in the affinity constant (47.60 micrograms/ml) under these conditions. These findings suggest that G. lamblia infection in mice leads to enhanced macromolecular absorption which seems unrelated to the binding of proteins to epithelial cell surface.