Activity of proximal promoter of the human beta(1)-integrin gene was increased in Sezary syndrome

Changes in beta (1)-integrin expression have been involved in abnormal cell ular interactions between malignant lymphocytes from Sezary (Sz) patients a nd keratinocytes. In this paper, we compare the activity of both distal and proximal promoters of the beta (1)-integrin gene in malignant lymphocytes from Sz patients with human normal lymphocytes. Activity of both beta (1)-i ntegrin promoters was also analysed in human normal keratinocytes. Northern blot analysis shows that beta (1)-integrin mRNA expression is higher in ma lignant Sz lymphocytes than in normal lymphocytes. CAT assays show that the activity of proximal beta1-integrin promoter is markedly increased (up to 6-fold) in malignant lymphocytes from Sz patients, in comparison to normal lymphocytes. These results suggest that changes in activity of the proximal promoter of beta1-integrin subunit could be, in part. responsible for the abnormal cellular interactions between malignant lymphocytes and keratinocy tes observed in Sz syndrome. (C) 2001 Elsevier Science Ltd. All rights rese rved.