Identification of a Novel Bone Morphogenetic Protein-responsive Gene That May Function as a Noncoding RNA

doi:10.1074/jbc.273.27.17079

Identification of a Novel Bone Morphogenetic Protein-responsive Gene That May Function as a Noncoding RNA*

From the ^‡Department of Biochemistry, The Cancer Institute, Tokyo, Japanese Foundation for Cancer Research (JFCR), 1-37-1 Kami-Ikebukuro, Toshima-ku, Tokyo 170-8455, Japan and ^‖Creative Biomolecules, Inc., Hopkinton, Massachusetts 01748

Abstract

Bone morphogenetic proteins (BMPs)/osteogenic proteins (OPs), members of the transforming growth factor-β superfamily, have a wide variety of effects on many cell types including osteoblasts and chondroblasts, and play critical roles in embryonic development. BMPs transduce their effects through binding to two different types of serine/threonine kinase receptors, type I and type II. Signaling by these receptors is mediated by the recently identified Smad proteins. Despite the rapid progress in understanding of the signaling mechanism downstream of BMP receptors, the target genes of BMPs are poorly understood in mammals. Here we identified a novel gene, termedBMP/OP-responsive gene (BORG), in C2C12 mouse myoblast cell line which trans-differentiates into osteoblastic cells in response to BMPs. Expression of BORG was dramatically induced in C2C12 cells by the treatment with BMP-2 or OP-1 within 2 h and peaked at 12–24 h, whereas transforming growth factor-β had a minimal effect. BMP-dependent expression of BORG was also detected in other cell types which are known to respond to BMPs, suggesting that BORG is a common target gene of BMPs. Cloning and sequence analysis of BORG cDNA and the genomic clones revealed that, unexpectedly, the transcript of BORG lacks any extensive open reading frames and contains a cluster of multiple interspersed repetitive sequences in its middle part. The unusual structural features suggested that BORG may function as a noncoding RNA, although it is spliced and polyadenylated as authentic protein-coding mRNAs. Together with the observation that transfection of antisense oligonucleotides of BORG partially inhibited BMP-induced differentiation in C2C12 cells, it is possible that a new class of RNA molecules may have certain roles in the differentiation process induced by BMPs.

Footnotes

↵* This work was supported by grants-in-aid for scientific research from the Ministry of Education, Science, and Culture of Japan.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AB010885.
↵§ Present address: Dept. of Biomaterials Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
↵¶ To whom correspondence should be addressed: Dept. of Biomaterials Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Tel.: 81-3-5803-5471; Fax: 81-3-5803-0192; E-mail: ichijo.det2{at}dent.tmd.ac.jp.
↵1 The abbreviations used are: BMP, bone morphogenetic protein; OP, osteogenic protein; BORG, BMP/OP-responsive gene; DMEM, Dulbecco’s modified Eagle’s medium; FBS, fetal bovine serum; GAPDH, glyceraldehydephosphate dehydrogenase; RACE, rapid amplification of cDNA ends; SINE, short interspersed nucleotide element; TGF-β, transforming growth factor-β; bp, base pair(s); ORF, open reading frame; PCR, polymerase chain reaction; RT, reverse transcriptase.
↵2 Smit, A. F. A., and Green, P.,RepeatMasker, http://ftp.genome.washington; edu/RM/RepeatMasker.html.
- Received December 16, 1997.
- Revision received April 23, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.