Alterations in local chromatin environment are involved in silencing and activation of subtelomeric var genes in Plasmodium falciparum
Details
Publication Year 2007-10, Volume 66, Issue #1, Page 139-150
Journal Title
MOLECULAR MICROBIOLOGY
Publication Type
Journal Article
Abstract
Plasmodium falciparum erythrocyte membrane protein I(PfEMP1), encoded by the var gene family, undergoes antigenic variation and plays an important role in chronic infection and severe malaria. Only a single var gene is transcribed per parasite, and epigenetic control mechanisms are fundamental in this strategy of mutually exclusive transcription. We show that subtelomeric upsB var gene promoters carried on episomes are silenced by default, and that promoter activation is sufficient to silence all other family members. However, they are active by default when placed downstream of a second active var promoter, underscoring the significance of local chromatin environment and nuclear compartmentalization in var promoter regulation. Native chromatin covering the SPE2-repeat array in upsB promoters is resistant to nuclease digestion, and insertion of these regulatory elements into a heterologous promoter causes local alterations in nucleosomal organization and promoter repression. Our findings suggest a common logic underlying the transcriptional control of all var genes, and have important implications for our understanding of the epigenetic processes involved in the regulation of this major virulence gene family.
Publisher
BLACKWELL PUBLISHING
Keywords
ERYTHROCYTE-MEMBRANE PROTEIN-1; MUTUALLY EXCLUSIVE EXPRESSION; HUMAN CEREBRAL MALARIA; CHONDROITIN SULFATE-A; ANTIGENIC VARIATION; VIRULENCE GENES; INFECTED ERYTHROCYTES; MULTIGENE FAMILY; TRANSCRIPTION; RECEPTOR
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Creation Date: 2007-10-01 12:00:00
Last Modified: 0001-01-01 12:00:00
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