A novel EB-1-AIDA-1 isoform, AIDA-1c, interacts with the Cajal body protein coilinReport as inadecuate

A novel EB-1-AIDA-1 isoform, AIDA-1c, interacts with the Cajal body protein coilin - Download this document for free, or read online. Document in PDF available to download.

BMC Cell Biology

, 6:23

First Online: 29 April 2005Received: 31 January 2005Accepted: 29 April 2005


BackgroundCajal bodies CBs are nuclear suborganelles that play a role in the biogenesis of small nuclear ribonucleoproteins snRNPs, which are crucial for pre-mRNA splicing. Upon nuclear reentry, Sm-class snRNPs localize first to the CB, where the snRNA moiety of the snRNP is modified. It is not clear how snRNPs target to the CB and are released from this structure after their modification. Coilin, the CB marker protein, may participate in snRNP biogenesis given that it can interact with snRNPs and SMN. SMN is crucial for snRNP assembly and is the protein mutated in the neurodegenerative disease Spinal Muscular Atrophy. Coilin knockout mice display significant viability problems and altered CB formation. Thus characterization of the CB and its associated proteins will give insight into snRNP biogenesis and clarify the dynamic organization of the nucleus.

ResultsIn this report, we identify a novel protein isoform of EB-1-AIDA-1, termed AIDA-1c, that interacts with the CB marker protein, coilin. Northern and nested PCR experiments reveal that the AIDA-1c isoform is expressed in brain and several cancer cell lines. Competition binding experiments demonstrate that AIDA-1c competes with SmB- for coilin binding sites, but does not bind SMN. When ectopically expressed, AIDA-1c is predominantly nuclear with no obvious accumulations in CBs. Interestingly, another EB-1-AIDA-1 nuclear isoform, AIDA-1a, does not bind coilin in vivo as efficiently as AIDA-1c. Knockdown of EB-1-AIDA-1 isoforms by siRNA altered Cajal body organization and reduced cell viability.

ConclusionThese data suggest that specific EB-1-AIDA-1 isoforms, such as AIDA-1c, may participate in the regulation of nucleoplasmic coilin protein interactions in neuronal and transformed cells.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2121-6-23 contains supplementary material, which is available to authorized users.

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Author: Hongzhi Xu - Michael D Hebert

Source: https://link.springer.com/article/10.1186/1471-2121-6-23

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