Methylation pattern of Activator transposase binding sites in maize endosperm.

Wang, Lihua; Heinlein, Manfred; Kunze, Reinhard

doi:10.1105/tpc.8.4.747

Cited by 44 publications

(18 citation statements)

References 46 publications

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“…When applying PPT selection on T 2 and T 3 seeds, the recovery of resistant plants was much lower than expected from the normal genetic segregation ratios (Enckevort and Pereira, unpublished results). In agreement with previous reports (Schwartz and Dennis 1986;Wang et al 1996), this would suggest the occurrence of methylation of the Ds as a cause for inhibition of transposition, though in this case methylation seems to spread over the whole transposon instead of being restricted to the terminal regions.…”

Section: Ds Transposition Behavioursupporting

confidence: 87%

Transpositional behaviour of an Ac/Ds system for reverse genetics in rice

Greco¹,

Ouwerkerk

Kam

et al. 2003

Theor Appl Genet

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A collection of transposon Ac/ Ds enhancer trap lines is being developed in rice that will contribute to the development of a rice mutation machine for the functional analysis of rice genes. Molecular analyses revealed high transpositional activity in early generations, with 62% of the T0 primary transformants and more than 90% of their T1 progeny lines showing ongoing active transposition. About 10% of the lines displayed amplification of the Ds copy number. However, inactivation of Ds seemed to occur in about 70% of the T2 families and in the T3 generation. Southern blot analyses revealed a high frequency of germinal insertions inherited in the T1 progeny plants, and transmitted preferentially over the many other somatic inserts to later generations. The sequencing of Ds flanking sites in subsets of T1 plants indicated the independence of insertions in different T1 families originating from the same T0 line. Almost 80% of the insertion sites isolated showing homology to the sequenced genome, resided in genes or within a range at which neighbouring genes could be revealed by enhancer trapping. A strategy involving the propagation of a large number of T0 and T1 independent lines is being pursued to ensure the recovery of a maximum number of independent insertions in later generations. The inactive T2 and T3 lines produced will then provide a collection of stable insertions to be used in reverse genetics experiments. The preferential insertion of Ds in gene-rich regions and the use of lines containing multiple Ds transposons will enable the production of a large population of inserts in a smaller number of plants. Additional features provided by the presence of lox sites for site-specific recombination, or the use of different transposase sources and selectable markers, are discussed.

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Section: Ds Transposition Behavioursupporting

confidence: 87%

Transpositional behaviour of an Ac/Ds system for reverse genetics in rice

Greco¹,

Ouwerkerk

Kam

et al. 2003

Theor Appl Genet

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“…This indicates that the previously reported preferential transposition of Ac during the S phase of the cell cycle (Greenblatt and Brink 1963;Chen et al 1992) cannot be due solely to control of transposase production at the transcriptional level. These data also support a model in which cell-cycle regulation of transposition might be determined at the DNA level, due to a higher binding anity of the transposase for newly replicated hemimethylated target sites (Wang et al 1996).…”

Section: Discussionsupporting

confidence: 67%

“…The preferential transposition of Ac/Ds elements during DNA replication (Greenblatt and Brink 1963;Chen et al 1992) is also an example of host-mediated regulation of transposition. It has been proposed that cell-cycle regulation of Ac transposition is caused by an anity of the transposase for newly replicated, hemimethylated DNA (Wang et al 1996). However, cell-cycle regulation of transposase expression could also be mediated at the transcriptional level.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Ac promoter: structure and regulation

Fridlender¹,

Sitrit²,

Shaul³

et al. 1998

Mol Gen Genet

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The Ac-encoded transposase, a factor that is essential for the mobility of the Ac element, is expressed under the control of a promoter that lacks a conventional TATA box. The regulation of this promoter is poorly understood. We have analyzed Ac promoter structure and activity, both in vitro and in vivo, using transgenic tobacco plants and cell suspensions. A deletion analysis of the Ac 5' region showed that the minimal promoter is located within 70 bp of the major transcription initiation site (at position 334). The minimal promoter includes the sequence TAAGAAATA at position 294 303, i.e., about 30 nucleotides upstream from the transcription start site. This sequence binds specifically to the TATA-binding protein (TBP), suggesting that it is functional as a TATA box. The regulation of the Ac promoter was studied throughout plant development. Levels of Ac mRNA were low in all tissues studied, with higher expression being observed in dividing cells. In order to test whether Ac promoter is regulated during the cell cycle, a tobacco cell suspension transformed with Ac, was grown synchronously. No differences were found in Ac mRNA levels between cells in S, G2, M, or G1 phases; however, expression was lower in the stationary phase. We conclude that Ac promoter is not cell-cycle regulated but is expressed at a higher level in dividing cells. The possible relationship between promoter features and the regulation of Ac element transposition is discussed.

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“…This chromatid selectivity can be explained by the methylation status of the transposon: a holomethylated transposon is unable to transpose, whereas the two daughter transposons produced by replication will be hemimethylated on distinct DNA strands and one of these hemimethylated elements is a preferred transposase substrate (Wang et al 1996;Wang and Kunze 1998;Ros and Kunze 2001). These ®ndings are consistent with our proposal that transposase acts upon one of the newly replicated transposon ends, while the other transposon end is unreplicated and not yet competent for transposition.…”

Section: A Model For Ac Transposition During Element Replicationmentioning

confidence: 99%

Ac transposition is impaired by a small terminal deletion

Xiao

Peterson

2002

Mol Gen Genomics

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In maize, the P1-vv allele specifies variegated pericarp and cob pigmentation, and contains an Ac transposable element inserted in the second intron of the P1-rr gene. Starting from P1-vv, we recovered a new allele, called P1-vv5145, which gives an extremely light variegated pericarp and cob phenotype. The P1-vv5145 allele contains an Ac element ( Ac5145) at the same position and in the same orientation as in the progenitor P1-vv allele; however, the P1-vv5145 allele has a 2-bp deletion which removes the last nucleotide (A) from the 3' end of the Ac element, and an adjacent flanking nucleotide (C) from the p1 intron. In crosses with a Ds tester stock, P1-vv5145 shows a normal ability to induce Ds transposition; however, Ac excision from P1-vv5145 is 3800-fold less frequent than from the progenitor P1-vv allele. Our results demonstrate that the alteration of the 3' terminal base strongly impairs Ac transposition. The P1-vv5145 allele thus provides a relatively stable source of Ac transposase for controlling Ds transposition in genetic experiments. In addition, we describe two further alleles ( P1-ww7B8, P1-ww9A146-3) that contain deletions of Ac and flanking p1 gene sequences. These latter deletions are larger and involve the 5' end of the the Ac element. A model is proposed to explain the formation of one-sided deletions as a consequence of Ac transposition during replication of the element.

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Methylation pattern of Activator transposase binding sites in maize endosperm.

Cited by 44 publications

References 46 publications

Transpositional behaviour of an Ac/Ds system for reverse genetics in rice

Transpositional behaviour of an Ac/Ds system for reverse genetics in rice

Analysis of the Ac promoter: structure and regulation

Ac transposition is impaired by a small terminal deletion

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