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Unusual chromatin structure associated with monoparalogous transcription of the Babesia bovis ves multigene family
- Source :
- International Journal for Parasitology. 43:163-172
- Publication Year :
- 2013
- Publisher :
- Elsevier BV, 2013.
-
Abstract
- Rapid antigenic variation in Babesia bovis involves the variant erythrocyte surface antigen-1 (VESA1), a heterodimeric protein with subunits encoded by two branches of the ves multigene family. The ves1α and ves1β gene pair encoding VESA1a and 1b, respectively, are transcribed in a monoparalogous manner from a single locus of active ves transcription (LAT), just one of many quasi-palindromic ves loci. To determine whether this organization plays a role in transcriptional regulation, chromatin structure was first assessed. Limited treatment of isolated nuclei with micrococcal nuclease to assay nucleosomal patterning revealed a periodicity of 156-159 bp in both bulk chromatin and specific gene coding regions. This pattern also was maintained in the intergenic regions (IGr) of non-transcribed ves genes. In contrast, the LAT IGr adopts a unique pattern, yielding an apparent cluster of five closely-spaced hypersensitive sites flanked by regions of reduced nucleosomal occupancy. ves loci fall into three patterns of overall sensitivity to micrococcal nuclease or DNase I digestion, with only the LAT being consistently very sensitive. Non-transcribed ves genes are inconsistent in their sensitivity to the two enzymatic probes. Non-linear DNA structure in chromatin was investigated to determine whether unique structure arising as a result of the quasi-palindromic nature of the LAT may effect transcriptional control. The in vitro capacity of ves IGr sequences to adopt stable higher-order DNA structure is demonstrated here, but the presence of such structure in vivo was not supported. Based upon these results a working model is proposed for the chromatin structural remodeling responsible for the sequential expression of ves multigene family members from divergently-organized loci.
- Subjects :
- Transcription, Genetic
Protozoan Proteins
Cattle Diseases
Article
Chromatin remodeling
Transcription (biology)
Babesiosis
Animals
Nucleosome
Coding region
Gene
Genetics
Regulation of gene expression
biology
Chromatin
Nucleosomes
Infectious Diseases
Gene Expression Regulation
Multigene Family
Babesia bovis
biology.protein
Nucleic Acid Conformation
Cattle
Parasitology
Micrococcal nuclease
Subjects
Details
- ISSN :
- 00207519
- Volume :
- 43
- Database :
- OpenAIRE
- Journal :
- International Journal for Parasitology
- Accession number :
- edsair.doi.dedup.....8adb36393d34818f3084dce57fbb7964