Dataset Information

Arabidopsis primary microRNA processing proteins HYL1 and DCL1 define a nuclear body distinct from the Cajal body.

ABSTRACT: Small regulatory microRNAs (miRNAs) are encoded in long precursors and are released from them during processing by cleavage within partially duplexed stem-loop structures. In the present work we investigated the role of the Arabidopsis nuclear RNA-binding protein HYL1 and the nuclear RNase III enzyme DCL1 in processing of primary miRNA (pri-miR171a). The miR171a gene is complex, with multiple transcription start sites, as well as alternative splicing of exons and alternative polyadenylation sites. Both HYL1 and DCL1 proteins are required for processing of the major pri-miR171a, spliced and polyadenylated forms of which accumulate in plants homozygous for mutations in either gene, but not in wild-type plants. In transiently transfected Arabidopsis protoplasts, HYL1-mCherry and YFP-DCL1 fusion proteins colocalize to small nuclear bodies similar to Cajal bodies but lacking the Cajal body marker Atcoilin. The HYL1 protein coimmunoprecipitates with miR171a and miR159a precursors, indicating that it is an integral component of the precursor processing machinery. Thus, the distinct HYL1- and DCL1-containing nuclear bodies may be miRNA precursor processing sites. Alternatively, they may be assembly and storage sites for the miRNA precursor processing machinery.

SUBMITTER: Song L

PROVIDER: S-EPMC1838471 | biostudies-other | 2007 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Arabidopsis primary microRNA processing proteins HYL1 and DCL1 define a nuclear body distinct from the Cajal body.

Song Liang L Han Meng-Hsuan MH Lesicka Joanna J Fedoroff Nina N

Proceedings of the National Academy of Sciences of the United States of America 20070316 13

Small regulatory microRNAs (miRNAs) are encoded in long precursors and are released from them during processing by cleavage within partially duplexed stem-loop structures. In the present work we investigated the role of the Arabidopsis nuclear RNA-binding protein HYL1 and the nuclear RNase III enzyme DCL1 in processing of primary miRNA (pri-miR171a). The miR171a gene is complex, with multiple transcription start sites, as well as alternative splicing of exons and alternative polyadenylation site ...[more]

PMID: 17369351

Similar Datasets

Project description:We have examined the distribution of RNA transcription and processing factors in the amphibian oocyte nucleus or germinal vesicle. RNA polymerase I (pol I), pol II, and pol III occur in the Cajal bodies (coiled bodies) along with various components required for transcription and processing of the three classes of nuclear transcripts: mRNA, rRNA, and pol III transcripts. Among these components are transcription factor IIF (TFIIF), TFIIS, splicing factors, the U7 small nuclear ribonucleoprotein particle, the stem-loop binding protein, SR proteins, cleavage and polyadenylation factors, small nucleolar RNAs, nucleolar proteins that are probably involved in pre-rRNA processing, and TFIIIA. Earlier studies and data presented here show that several of these components are first targeted to Cajal bodies when injected into the oocyte and only subsequently appear in the chromosomes or nucleoli, where transcription itself occurs. We suggest that pol I, pol II, and pol III transcription and processing components are preassembled in Cajal bodies before transport to the chromosomes and nucleoli. Most components of the pol II transcription and processing pathway that occur in Cajal bodies are also found in the many hundreds of B-snurposomes in the germinal vesicle. Electron microscopic images show that B-snurposomes consist primarily, if not exclusively, of 20- to 30-nm particles, which closely resemble the interchromatin granules described from sections of somatic nuclei. We suggest the name pol II transcriptosome for these particles to emphasize their content of factors involved in synthesis and processing of mRNA transcripts. We present a model in which pol I, pol II, and pol III transcriptosomes are assembled in the Cajal bodies before export to the nucleolus (pol I), to the B-snurposomes and eventually to the chromosomes (pol II), and directly to the chromosomes (pol III). The key feature of this model is the preassembly of the transcription and processing machinery into unitary particles. An analogy can be made between ribosomes and transcriptosomes, ribosomes being unitary particles involved in translation and transcriptosomes being unitary particles for transcription and processing of RNA.

Dataset Information

Arabidopsis primary microRNA processing proteins HYL1 and DCL1 define a nuclear body distinct from the Cajal body.

Publications

Arabidopsis primary microRNA processing proteins HYL1 and DCL1 define a nuclear body distinct from the Cajal body.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets