A homologue of the 65 kDa regulatory subunit of protein phosphatase 2A in early pea (Pisum sativum L.) embryos

Im, Evans; Fawcett, Tony; Boulter, D.; Ap, Fordham-Skelton

doi:10.1007/bf00023566

Cited by 13 publications

(13 citation statements)

References 37 publications

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“…We have recently reported on isolation of a partial cDNA pME1 encoding a homologue for the 65 kDa regulatory subunit of PP2A from early pea (Pisum sativum L.) embryos [10]. Southern blot analysis demonstrated that in pea and rape the catalytic and regulatory subunits of PP2A are encoded by multigene families.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of cDNA and genomic clones encoding homologues of the 65 kDa regulatory subunit of protein phosphatase 2A in Arabidopsis thaliana

et al. 1994

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Two cDNA species encoding sequences homologous to the 65 kDa regulatory subunit (PR 65) of protein phosphatase 2A (PP2A) have been isolated from an Arabidopsis thaliana cDNA library. These were designated pDF1 and pDF2. pDF1 is 1795 bp long and by comparison with the human and porcine PP2A regulatory subunit sequences represents a full-length clone. It encodes a predicted polypeptide of 587 amino acid residues. pDF2 is truncated at the 5' end by 237 bp. The complete nucleotide sequences have been determined for both cDNA species. Comparison of the nucleotide and the deduced amino acid sequences showed that the two sequences were homologous but not identical and therefore must be derived from two different genes. Northern blot analysis was performed on total RNA and poly(A)+ RNA isolated from seed at various stages of development and from young leaf material of Brassica napus L. (oilseed rape). Both cDNA probes hybridised to a single major mRNA species of ca. 2.2 kb. The highest level of expression was observed in the total RNA from developing rape seed at about 33 days after flowering, and the transcript level in the poly(A)+ RNA of the seed was higher than in young leaf of oilseed rape. Southern blot analysis was performed on two varieties of A. thaliana and B. napus genomic DNA; this identified a small family of genes in A. thaliana consisting of at least 2 or 3 members and a larger multigene family in B. napus of at least 5 or 6 members. Two independent genomic clones were isolated from an A. thaliana genomic library. Sequencing of a fragment common to both revealed that the sequence was identical in both clones and, therefore, they were assumed to contain the same genomic sequence. The genomic sequence selected, designated regA, is 3639 bp long and the coding sequence contains eleven introns. The gene encodes a predicted polypeptide of 590 amino acid residues. The sequence comparison with both cDNA sequences showed that it is homologous but not identical to the two, confirming that at least three different genes exist in A. thaliana which encode PR65 of PP2A.

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Section: Introductionmentioning

confidence: 99%

Characterisation of cDNA and genomic clones encoding homologues of the 65 kDa regulatory subunit of protein phosphatase 2A in Arabidopsis thaliana

et al. 1994

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“…This region is followed by a highly variable section (see above), then a long conserved stretch (201 amino acids) and lastly a highly variable carboxy terminus. Considering that the catalytic subunit of PP2A is very highly conserved (79~o identity among human and plant) [1,31] it is of interest that both regulatory subunits A and B are much more variable (55~o and 45~o identity respectively between human and plant) [3]. Clearly, as would be expected, evolutionary constraints on proteins are much greater for catalysis compared to protein interaction for regulation.…”

Section: Discussionmentioning

confidence: 95%

“…AtBc~ mRNA accumulates in all tissues examined, it is possible that the product of AtBc~ interacts with more than one isoform of PP2Ac. Lastly, PP2A c from animals interact with a number of other regulatory subunits [27], and recently one of these subunits (regulatory subunit A) has also been identified in Arabidopsis and in pea [3,39]. Both these plant species contain a number of A regulatory subunit genes and in Arabidopsis at least two of these genes are expressed [39].…”

Section: Discussionmentioning

confidence: 99%

Characterization of a cDNA encoding the 55 kDa B regulatory subunit of Arabidopsis protein phosphatase 2A

et al. 1995

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Type 2A serine/threonine protein phosphatases (PP2A) are key components in the regulation of signal transduction and control of cell metabolism. The activity of these protein phosphatases is modulated by regulatory subunits. While PP2A activity has been characterized in plants, little is known about its regulation. We used the polymerase chain reaction to amplify a segment of a cDNA encoding the B regulatory subunit of PP2A from Arabidopsis. The amplified DNA fragment of 372 nucleotides was used as a probe to screen an Arabidopsis cDNA library and a full-length clone (AtB alpha) of 2.1 kbp was isolated. The predicted protein encoded by AtB alpha is 43 to 46% identical and 53 to 56% similar to its yeast and mammalian counterparts, and contains three unique regions of amino acid insertions not present in the animal B regulatory subunit. Genomic Southern blots indicate the Arabidopsis genome contains at least two genes encoding the B regulatory subunit. In addition, other plant species also contain DNA sequences homologous to the B regulatory subunit, indicating that regulation of PP2A activity by the 55 kDa B regulatory subunit is probably ubiquitous in plants. Northern blots indicate the AtB alpha mRNA accumulates in all Arabidopsis tissues examined, suggesting the protein product of the AtB alpha gene performs a basic housekeeping function in plant cells.

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“…In every case the mRNAs derived from each gene are detected in all tissues albeit at different levels [3,9,15]. In addition, m R N A encoding the 65 kDa protein was also detected during all stages of pea development and in pea roots [6], as well as during all stages of oilseed rape development and in Brassica napus leaves [21].…”

Section: N T G M V G S S N S S R S S I a G G E G A N S E D S G T E M mentioning

confidence: 96%

“…(AC)GNGTN(AC)GNTA(TC) A T G G T N G C encoding the amino acids RVRYMV and NGC-C C A ( T C ) A C N G G N C C (AG)AA(TC)TC reflecting the complementary strand of D N A encoding the amino acids E F G P V W A [6]. PCR reactions and conditions were as described in…”

Section: N T G M V G S S N S S R S S I a G G E G A N S E D S G T E M mentioning

confidence: 99%

Characterization of DNA sequences encoding a novel isoform of the 55 kDa B regulatory subunit of the type 2A protein serine/threonine phosphatase of Arabidopsis thaliana

et al. 1996

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We have identified a novel gene (AtB beta) encoding a previously uncharacterized isoform of the B regulatory subunit of the type 2A serine/threonine protein phosphatase (PP2A) of Arabidopsis, and show that mRNA derived from the AtB beta gene accumulates in all Arabidopsis organs. In addition, we examined the expression of the three genes encoding the A regulatory subunit of Arabidopsis PP2A and show these genes are expressed in all organs as well. Taken together, our results suggest a myriad of PP2A subunit combinations, possibly with distinct substrate specificities, may occur within each Arabidopsis cell.

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A homologue of the 65 kDa regulatory subunit of protein phosphatase 2A in early pea (Pisum sativum L.) embryos

Cited by 13 publications

References 37 publications

Characterisation of cDNA and genomic clones encoding homologues of the 65 kDa regulatory subunit of protein phosphatase 2A in Arabidopsis thaliana

Characterisation of cDNA and genomic clones encoding homologues of the 65 kDa regulatory subunit of protein phosphatase 2A in Arabidopsis thaliana

Characterization of a cDNA encoding the 55 kDa B regulatory subunit of Arabidopsis protein phosphatase 2A

Characterization of DNA sequences encoding a novel isoform of the 55 kDa B regulatory subunit of the type 2A protein serine/threonine phosphatase of Arabidopsis thaliana

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