Presence of an Activator (Ac)-like sequence in Pennisetum glaucum (pearl millet)

MacRae, Amy F.; Learn, Gerald H.; Karjala, Merja; Clegg, Michael T.

doi:10.1007/bf00017740

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…We estimate that maize and pearl millet last shared a common ancestor between 25 and 42 million years ago, based on chloroplast DNA rbcL sequence data and fossil evidence (Doebley et al, 1990;Gaut & Clegg, 1991). The estimated date when the two grasses diverged, the level of DNA sequence divergence, the reproductive isolation between the two grasses and resulting lack of current genetic exchange, all support the hypothesis that Ac-like sequences were present in the progenitor of maize and pearl millet (MacRae et al, 1990). This is a novel conclusion, since in general Ac-like sequences have not been reported in plants that are widely divergent from maize.…”

Section: Discussionmentioning

confidence: 50%

“…Phage DNA from a single positive plaque (EMPgAc-l) was then digested to completion with several restriction endonucleases. Southern blots were hybridized with the radiolabeled 1.6 kb Hindill internal Ac fragment from maize (MacRae et al, 1990). This positive hybridization served to confirm the cloning of an Ac-like element from Pennisetum.…”

Section: Cloning Of An Ac-like Element From Pennisetummentioning

confidence: 99%

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Evolution of Ac and Dsl elements in select grasses (Poaceae)

MacRae

Clegg

1992

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We present data on evolution of the Ac/Ds family of transposable elements in select grasses (Poaceae). An Ac-like element was cloned from a DNA library of the grass Pennisetum glaucum (pearl millet) and 2387 bp of it have been sequenced. When the pearl millet Ac-like sequence is aligned with the corresponding region of the maize Ac sequence, it is found that all sequences corresponding to intron II in maize Ac are absent in pearl millet Ac. Kimura's evolutionary distance between maize and pearl millet Ac sequences is estimated to be 0.429 +/- 0.020 nucleotide substitutions per site. This value is not significantly different from the average number of synonymous substitutions for coding regions of the Adh1 gene between maize and pearl millet, which is 0.395 +/- 0.051 nucleotide substitutions per site. If we can assume Ac and Adh1 divergence times are equivalent between maize and pearl millet, then the above calculations suggest Ac-like sequences have probably not been strongly constrained by natural selection. The level of DNA sequence divergence between maize and pearl millet Ac sequences, the estimated date when maize and pearl millet diverged (25-40 million years ago), coupled with their reproductive isolation/lack of current genetic exchange, all support the theory that Ac-like sequences have not been recently introduced into pearl millet from maize. Instead, Ac-like sequences were probably present in the progenitor of maize and pearl millet, and have thus existed in the grasses for at least 25 million years. Ac-like sequences may be widely distributed among the grasses. We also present the first 2 Ds1 controlling element sequences from teosinte species: Zea luxurians and Zea perennis. A total of 10 Ds1 elements had previously been sequenced from maize and a distant maize relative, Tripsacum. When a maximum likelihood network of genetic relationships is constructed for all 12 sequenced Ds1 elements, the 2 teosinte Ds1 elements are as distant from most maize Ds1 elements and from each other, as the maize Ds1 elements are from one another. Our new teosinte sequence data support the previous conclusion that Ds1 elements have been accumulating mutations independently since maize and Tripsacum diverged. We present a scenario for the origin of Ds1 elements.

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Section: Discussionmentioning

confidence: 50%

Section: Cloning Of An Ac-like Element From Pennisetummentioning

confidence: 99%

Evolution of Ac and Dsl elements in select grasses (Poaceae)

MacRae

Clegg

1992

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“…3A). Rice STC OSJNBa0076F14f is probably a rice ortholog of Activator, because the branching pattern of maize, pearl millet, and rice is the same as would be expected from a species phylogeny (Macrae et al 1990(Macrae et al , 1994Paterson et al 1996). Clearly, the rice STC OSJNBa0005B04f is a paralog of Activator and may have diverged from the line leading to Activator and snapdragon Tam3 early in plant evolution.…”

Section: Activatormentioning

confidence: 88%

Rice Transposable Elements: A Survey of 73,000 Sequence-Tagged-Connectors

et al. 2000

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As part of an international effort to sequence the rice genome, the Clemson University Genomics Institute is developing a sequence-tagged-connector (STC) framework. This framework includes the generation of deep-coverage BAC libraries from O. sativa ssp. japonica c.v. Nipponbare and the sequencing of both ends of the genomic DNA insert of the BAC clones. Here, we report a survey of the transposable elements (TE) in >73,000 STCs. A total of 6848 STCs were found homologous to regions of known TE sequences (E<10 −5 ) by FASTX search of STCs against a set of 1358 TE protein sequences obtained from GenBank. Of these TE-containing STCs (TE-STCs), 88% (6027) are related to retroelements and the remaining are transposase homologs. Nearly all DNA transposons known previously in plants were present in the STCs, including maize Ac/Ds, En/Spm, Mutator, and mariner-like elements. In addition, 2746 STCs were found to contain regions homologous to known miniature inverted-repeat transposable elements (MITEs). The distribution of these MITEs in regions near genes was confirmed by EST comparisons to MITE-containing STCs, and our results showed that the association of MITEs with known EST transcripts varies by MITE type. Unlike the biased distribution of retroelements in maize, we found no evidence for the presence of gene islands when we correlated TE-STCs with a physical map of the CUGI BAC library. These analyses of TEs in nearly 50 Mb of rice genomic DNA provide an interesting and informative preview of the rice genome.

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“…Both fragments are shown in Figure 1 of MacRae et al (1990). The pPACH and pPACP inserts overlap, the pPACH clone containing the 5' end and middle region of pearl millet Ac, and pPACP clone containing the 3' end and middle region of pearl millet Ac, relative to the approximately 4.6 kb Ac sequence from maize.…”

Section: Subcloningmentioning

confidence: 99%

“…Using chloroplast DNA rbcL sequence data and fossil evidence, plus assuming a molecular clock, we estimate that maize and pearl millet last shared a common ancestor between 25 and 42 million years ago (Doebley et al, 1990;Gaut & Clegg, 1991;MacRae et al, 1990). This estimated pearl millet / maize organismal divergence time and current reproductive isolation, coupled with the relatively high level of Ac sequence divergence compared to Adhl sequence divergence, and the structural differences between Mzeac 1 and Pac 1 sequences, suggest that Pac 1 was not a recent introduction into pearl millet.…”

Section: Ancient Origins Of Ac Sequences In Grassesmentioning

confidence: 99%

Molecular evolutionary characterization of an Activator (Ac)-like transposable element sequence from pearl millet (Pennisetum glaucum) (Poaceae)

1994

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We present data on the evolution of the Ac/Ds family of transposable elements in select grasses (Poaceae). A defective Ac-like element was cloned from a DNA library of the grass Pennisetum glaucum (pearl millet) and its entire 4531 bp sequence has been determined. When the pearl millet Ac-like sequence is aligned with the maize Ac sequence, it is found that there is approximately 70% DNA similarity in the central region spanning most of maize Ac exon II and all of exon III. In addition, there are two smaller regions of similarity at the Ac terminii. Besides these three major structural similarities, Pennisetum Ac has two large regions, one 5' and one 3', that show little similarity to Zea Ac. Furthermore, most of the sequences corresponding to intron II in maize Ac are absent in pearl millet Ac. Kimura's evolutionary distance between the central region of maize and pearl millet Ac sequences is estimated to be 0.429 +/- 0.020 nucleotide substitutions per site. This value is not significantly different from the average number of synonymous substitutions for coding regions of the Adh1 gene between maize and pearl millet, which is 0.395 +/- 0.051 nucleotide substitutions per site. If we assume Ac and Adh1 divergence times are equivalent between maize and pearl millet, then the above calculations suggest Ac-like sequences have probably not been strongly constrained by natural selection. Conserved DNA and amino acid sequence motifs are also examined. The level of DNA sequence divergence between maize and pearl millet Ac sequences, the estimated date when maize and pearl millet diverged (25-40 million years ago), coupled with their reproductive isolation/lack of current genetic exchange, all support the theory that Ac-like sequences have not been recently introduced into pearl millet from maize. Instead, Ac-like sequences were probably present in the progenitor of maize and pearl millet and have thus existed in the grasses for at least 25 million years.

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Presence of an Activator (Ac)-like sequence in Pennisetum glaucum (pearl millet)

Cited by 10 publications

References 17 publications

Evolution of Ac and Dsl elements in select grasses (Poaceae)

Evolution of Ac and Dsl elements in select grasses (Poaceae)

Rice Transposable Elements: A Survey of 73,000 Sequence-Tagged-Connectors

Molecular evolutionary characterization of an Activator (Ac)-like transposable element sequence from pearl millet (Pennisetum glaucum) (Poaceae)

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