The class II transactivator is a major transcriptional factor acting on the promoters of MHC class II genes. Transcription of the CIITA gene is driven by four alternative promoters, which exhibit cell-type-specific activity. The CIITA promoter III (PIII) is constitutively active in B cells, whereas promoter IV (PIV) becomes activated upon interferon-γ activation. The aim of this study was to investigate whether these two promoters exhibit a sequence variability like the MHC class II promoters do. We isolated PIII and PIV fragments from healthy individuals and rheumatoid arthritis patients and screened them for sequence polymorphisms. Single base pair substitutions within the CIITA PIV were found in 9% of the individuals analyzed. The majority of the substitutions were located upstream of the known cis-acting elements of the promoter. PIII was non-polymorphic. To evaluate the functional relevance of the detected polymorphism we cloned variable PIV upstream of the luciferase reporter gene. Such prepared constructs were transfected into monocytes, melanoma and HeLa cells, which were subsequently stimulated with interferon-γ. The analysis of promoter activities did not reveal significant differences in all three cell types. We conclude that the level of CIITA expression does not vary within the population. Thus the differences in the level of MHC class II expression, which are observed between individuals, stem for the polymorphisms of the MHC class II promoters themselves.

This content is only available via PDF.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.