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© The Rockefeller University Press,
0021-9525/2000//939 $5.00
The Journal of Cell Biology, Volume 150, Number 5,
, 2000 939-948
Original Article |
Atrophin-1, the Dentato-Rubral and Pallido-Luysian Atrophy Gene Product, Interacts with Eto/Mtg8 in the Nuclear Matrix and Represses Transcription
jonwood{at}jhmi.edu
Dentato-rubral and pallido-luysian atrophy (DRPLA) is one of the family of neurodegenerative diseases caused by expansion of a polyglutamine tract. The drpla gene product, atrophin-1, is widely expressed, has no known function or activity, and is found in both the nuclear and cytoplasmic compartments of neurons. Truncated fragments of atrophin-1 accumulate in neuronal nuclei in a transgenic mouse model of DRPLA, and may underlie the disease phenotype.
Using the yeast two-hybrid system, we identified ETO/MTG8, a component of nuclear receptor corepressor complexes, as an atrophin-1–interacting protein. When cotransfected into Neuro-2a cells, atrophin-1 and ETO/MTG8 colocalize in discrete nuclear structures that contain endogenous mSin3A and histone deacetylases. These structures are sodium dodecyl sulfate–soluble and associated with the nuclear matrix. Cotransfection of ETO/MTG8 with atrophin-1 recruits atrophin-1 to the nuclear matrix, while atrophin-1 and ETO/MTG8 cofractionate in nuclear matrix preparations from brains of DRPLA transgenic mice. Furthermore, in a cell transfection–based assay, atrophin-1 represses transcription. Together, these results suggest that atrophin-1 associates with nuclear receptor corepressor complexes and is involved in transcriptional regulation.
Emerging links between disease-associated polyglutamine proteins, nuclear receptors, translocation-leukemia proteins, and the nuclear matrix may have important repercussions for the pathobiology of this family of neurodegenerative disorders.
Key Words: trinucleotide repeats neurodegenerative diseases cerebellar nuclei nuclear matrix myeloid leukemia
© 2000 The Rockefeller University Press
Abbreviations used in this paper: CBP, CREB-binding protein; DBD, DNA-binding domain; DRPLA, dentato-rubral and pallido-luysian atrophy; ETO, product of eight-twenty-one myeloid translocation gene on chromosome 8; HDAC, histone deacetylase; MTG8, product of myeloid translocation gene on chromosome 8; MTG16, product of myeloid translocation gene on chromosome 16; MTGR1, MTG8-related protein 1; N-CoR, nuclear receptor corepressor; PML, promyelocytic leukemia protein; POD, promyelocytic leukemia antigen oncogenic domain; SMRT, silencing mediator for retinoid and thyroid hormone receptors; VRC, vanadyl ribonucleoside complex.
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