Molecular Characterization of the Abp1 5′-Flanking Region in Maize and the Teosintes

Journal of Biological Chemistry

2001

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The discovery that vertebrate retroviruses could transduce cellular sequences was central to cancer etiology and research. Although not well documented, transduction of cellular sequences by retroelements has been suggested to modify cellular functions. The maize Bs1 transposon was the first non-vertebrate retroelement reported to have transduced a portion of a cellular gene (c-pma). We show that Bs1 has, in addition, transduced portions of at least two more maize cellular genes, namely for 1,3-␤-glucanase (c-bg) and 1,4-␤-xylan endohydrolase (c-xe). We also show that Bs1 has maintained a truncated gag domain with similarity to the magellan gypsy-like long terminal repeat retrotransposon and a region that may correspond to an env-like domain. Our findings suggest that, like oncogenic retroviruses, the three transduced gene fragments and the Bs1 gag domain encode a fusion protein that has the potential to be expressed. We suggest that transduction by retroelements may facilitate the formation of novel hybrid genes in plants.

Section: Methodsmentioning

confidence: 99%

A Novel Hybrid Open Reading Frame Formed by Multiple Cellular Gene Transductions by a Plant Long Terminal Repeat Retroelement

Journal of Biological Chemistry

2001

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“…Second, we used the same cDNA to amplify transcripts of an intron-containing gene. For this purpose, we used the gene coding for Abp1 (for auxinbinding protein 1; Elrouby and Bureau, 2000). Abp1 primers anchored in exons 3 and 5 yield an RT-PCR product consistent with amplification from cDNA only (Fig.…”

Section: Bs1 Orf1 Is Expressed In Reproductive Organsmentioning

confidence: 99%

Bs1, a New Chimeric Gene Formed by Retrotransposon-Mediated Exon Shuffling in Maize

2010

Plant Physiology

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Transposons are major components of all eukaryotic genomes. Although traditionally regarded as causes of detrimental mutations, recent evidence suggests that transposons may play a role in host gene diversification and evolution. For example, host gene transduction by retroelements has been suggested to be both common and to have the potential to create new chimeric genes by the shuffling of existing sequences. We have previously shown that the maize (Zea mays subsp. mays) retrotransposon Bs1 has transduced sequences from three different host genes. Here, we provide evidence that these transduction events led to the generation of a chimeric new gene that is both transcribed and translated. Expression of Bs1 is tightly controlled and occurs during a narrow developmental window in early ear development. Although all Bs1-associated transduction events took place before Zea speciation, a full uninterrupted open reading frame encoding the BS1 protein may have arisen in domesticated maize or in the diverse populations of its progenitor Z. mays subsp. parviglumis. We discuss potential functions based on domain conservation and evidence for functional constraints between the transduced sequences and their host gene counterparts.

“…While ABP1 is likely encoded by a single gene copy in Arabidopsis and maize, multiple gene copies exist in the wild relatives of maize (the teosinte) (Elrouby and Bureau 2000;Chen et al 2001). Two other genes (ABP4 and ABP5) encoding auxin-binding proteins were identified and found to encode proteins that are almost identical (three amino acid substitutions) but that share only 76% identity with ABP1 (Schwob et al 1993), suggesting that among the genes encoding the auxin-binding family of proteins, ABP1 likely diverged considerably.…”

Section: Introductionmentioning

confidence: 99%

Modulation of AUXIN-BINDING PROTEIN 1 gene expression in maize and the teosintes by transposon insertions in its promoter

2011

Mol Genet Genomics

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Auxin plays crucial roles in plant development. Auxin-binding protein 1 (ABP1) is an auxin receptor required to coordinate cell division and expansion during postembryonic shoot development, and differential auxin responses during root growth. While ABP1 is encoded by a single gene in maize, multiple gene copies exist in teosinte, the wild relatives of maize. We have previously shown that some of the differences between these genes are caused by multiple transposon insertions in the promoter. Here we show that the different ABP1 promoter types confer differential gene expression levels on a firefly luciferase reporter gene. We also discovered a negative regulatory sequence upstream of the conserved transcriptional start site. When this sequence is insulated by an Ac-like transposon or deleted in natural ABP1 gene variants, expression levels are enhanced. Promoters combining both a MITE and a solo-LTR showed small but significant increase in expression compared to those containing only one insertion. This increase seems to be additive, suggesting that it may be due to enhancer sequences present within these transposons. Our results point to a potential role of the ABP1-associated transposons in the modulation of ABP1 gene expression.