Transposable Elements of Antirrhinum Majus

Sommer, Hans; Hehl, Reinhard; Krebbers, Enno; Piotrowiak, Ralf; Lönnig, Wolf-Ekkehard; Saedler, Heinz

doi:10.1007/978-1-4684-5550-2_16

Cited by 25 publications

(13 citation statements)

References 17 publications

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“…This supports the conclusions of Hudson et al (1990), who examined another niv allele derived from niv™ c :98 that contained two copies of Tam3 that were located in new positions within 3 kb on either side of the former insertion site. The maize transposon Activator (known to be structurally related to Tam3: Sommer et al, 1988b;Hehl et al, 1991) transposes shortly after replication (Greenblatt and Brink, 1962;Chen et al, 1987), preferentially to closely linked chromosomal positions (Van Schaik and Brink, 1959;Greenblatt, 1984;Jones et al, 1990); our data for Tam3 would support the view that structurally related transposons from different species show similar functional traits. We propose that the inversion of sequence in n;V rec :531 resulted from an aberrant version of this transposition process.…”

Section: Generation Of Inversions and The Mechanism Of Transposition supporting

confidence: 69%

Transposon-induced inversion in Antirrhinum modifies nivea gene expression to give a novel flower color pattern under the control of cycloidearadialis.

1993

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Section: Generation Of Inversions and The Mechanism Of Transposition supporting

confidence: 69%

Transposon-induced inversion in Antirrhinum modifies nivea gene expression to give a novel flower color pattern under the control of cycloidearadialis.

1993

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“…rad-609 had a Ram1-like insertion of Ϸ1.45 kb within the intron. rad-654 had an insertion of a Ϸ4.3-kb transposon belonging to the CACTA family (20,21) within the intron. The similarity of the rad-654 and rad-609 insertion sites may account for their similar phenotypes.…”

Section: Rad Mutant Phenotypes and Interactionsmentioning

confidence: 99%

Floral asymmetry involves an interplay between TCP and MYB transcription factors in Antirrhinum

Corley

Carpenter

Copsey

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

221

276

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To understand how genes control floral asymmetry, we have isolated and analyzed the role of the RADIALIS (RAD) gene in Antirrhinum. We show that the RAD gene encodes a small MYB-like protein that is specifically expressed in the dorsal region of developing flowers. RAD has a single MYB-like domain that is closely related to one of the two MYB-like domains of DIV, a protein that has an antagonistic effect to RAD on floral development. Interactions between RAD and other genes indicate that floral asymmetry depends on the interplay between two pairs of transcription factors. First, a pair of TCP proteins is expressed in dorsal regions of the floral meristem, leading to the activation of RAD in the dorsal domain. The RAD MYB-like protein then antagonizes the related DIV MYB-like protein, preventing DIV activity in dorsal regions. In addition to its role in dorsal regions, RAD acts nonautonomously on lateral regions either directly, through RAD protein movement, or indirectly, through a signaling molecule.F loral asymmetry is thought to have evolved many times independently as a specialized mechanism for pollinator interaction (1-3). In a few cases, most notably in Antirrhinum majus, the molecular genetic basis of floral asymmetry has begun to be understood. Four key genes have been shown to control dorsoventral asymmetry in Antirrhinum: CYCLOIDEA (CYC), DICHOTOMA (DICH), RADIALIS (RAD), and DIVARICATA (DIV) (4-8). Two of these genes, CYC and DICH, promote dorsal identity and encode proteins belonging to the TCP family of transcription factors. DIV promotes ventral identity and encodes a protein belonging to the MYB family of transcription factors, carrying two MYB-like domains. However, the mechanism by which CYC, DICH, and DIV interact remains unclear. To address this question, we have isolated and characterized RAD, the fourth member of this group of genes, and explored how it acts in combination with the other genes to establish floral asymmetry.Flowers of wild-type Antirrhinum are zygomorphic, having a single plane of symmetry (bilateral symmetry), in contrast to actinomorphic flowers, which have multiple planes of symmetry (radial symmetry) (3). The zygomorphy of Antirrhinum flowers reflects morphological distinctions between the upper (dorsal) and lower (lateral and ventral) organs of whorls two and three. In whorl two, each flower has two dorsal petals, two lateral petals, and one ventral petal, whereas whorl three comprises a single arrested dorsal stamen (staminode), two lateral stamens, and two ventral stamens (Fig. 1 a and b).The CYC and DICH genes are required for dorsoventral asymmetry in Antirrhinum and are expressed from an early stage in the dorsal domain of the floral meristem (5, 7, 9). At later stages, CYC expression persists throughout most of the dorsal domain, whereas DICH becomes restricted to the most dorsal half of the dorsal domain. Inactivation of both CYC and DICH results in peloric (radially symmetrical) flowers, in which all petals have ventral identity (Fig. 1h). In cyc or dich single ...

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“…The predominant smaller transcripts of En/Spm (tnpA) and Taml are not related in sequence. In contrast, the larger transcripts (tnpB) which contain sequences from the open reading frames, present in the centre of En/Spm and Taml, share significant homology at the amino acid level [28]. Hitherto, no gene structure has been established for Tgm and the structure of the fully intact element has not yet been reported.…”

Section: Analysis Of En/spm-encoded Functionsmentioning

confidence: 99%

“…The conservation of these polypeptide sequences indicates a common function of the encoded products. Since the 13 bp TIRs are also conserved within the 'CACTA' elements, it was speculated [10,28] that the putative product (tnpB) may interact with the 13 bp TIRs and in fact may represent the function which cleaves at the element's termini.…”

Section: Analysis Of En/spm-encoded Functionsmentioning

confidence: 99%