Molecular cloning, expression and characterization of the zebrafish bram1 gene, a BMP receptor-associated molecule

Abstract

We have identified a cDNA clone encoding BMP receptor-associated molecule 1 (BRAM1) from the zebrafish expressed sequence tag (EST) database. The 2606 bp full-length bram1 cDNA was cloned, and further confirmed by nucleotide sequencing. The zebrafish sequence encodes a protein of 195 amino acids with an evolutionarily conserved MYND domain, which displays approximately approximately 98% homology with human and mouse BRAM1, and approximately approximately 64% homology with C. elegans BRA-1 and BRA-2. The bram1 gene, composed of five exons and four introns, spans approximately approximately 14 kb on linkage group 14 of the zebrafish genome. RT-PCR and whole mount in situ hybridization analyses disclosed that zebrafish BRAM1 is a maternal factor. The protein interacts directly with zebrafish BMP Receptor type IA, as observed from GST-pull down and co-immunoprecipitation assays. Furthermore, cotransfection of zebrafish BRAM1 with the corresponding BMP receptor resulted in down-regulation of BMP-mediated signaling. Our results collectively indicate that BRAM1 plays a biological role during zebrafish development.

Mga Modulates Bmpr1a Activity by Antagonizing Bs69 in Zebrafish

“…To test these hypothesis, we firstly examined the gene expression pattern of mga, bs69 , and bmpr1a during zebrafish early embryogenesis. The three genes have similar expression patterns from blastula to late organogenesis as reported ( Wu et al, 2006 ; Rikin and Evans, 2010 ; Smith et al, 2011 ). During gastrulation, both bmpr1aa and mga transcription levels are high, whereas bs69 transcript levels are relatively low.…”

“…It has been previously shown that mammalian MGA directly interacts with BS69, and that BRAM1, a possible spliced form of BS69, may be involved in the regulation of BMPR1A activity ( Kurozumi et al, 1998 ; Ansieau and Leutz, 2002 ; Velasco et al, 2006 ; Wu et al, 2006 ). Therefore, we speculated that Mga may modulate Bmpr1a activity through Bs69 in zebrafish.…”

“…BS69 associates with lymphotoxin beta receptor (LTβR) and inhibits LTβR-mediated signaling transduction ( Liu et al, 2011 ). It has been shown that BRAM1, an alternatively spliced form of BS69, may inhibit Bmp signaling by interacting with the type I BMP receptor 1A ( Kurozumi et al, 1998 ; Morita et al, 2001 ; Wu et al, 2006 ). However, BRAM1 was thought likely to be an artificial product that generated from the library construction ( Velasco et al, 2006 ).…”

Roles of BMP Signaling Pathway in Lip and Palate Development

“…Finally, there is a set of intracellular proteins that act as signal transducers or regulators of BMP signaling. Among them, BMPRIa interacts with the TGFβ-activated kinase (TAK) binding protein 1 (TAB1) through the BMP receptor-associated molecule 1 (BRAM1), which downregulates BMP-mediated Smad signaling [59]. Likewise, the X-chromosome-linked inhibitor of apoptosis (XIAP) connects BMPRI with TAB1 and may act as a positive regulator of MAP kinase signaling [60].…”

The vignette for V13N3 issue

“…To date, two homologs of BRAM1 in C. elegaus (BRA-1 and BRA-2) have been identified, and BRA-1 negatively regulates TGF-b signaling by blocking physical interaction between the type 1 receptor and Smads [17]. Wu et al [18] isolated zebrafish bram1, and found that BRAM1 directly interacts with the BMP receptors resulting in down-regulation of BMP signaling in cells.…”