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Plant spliceosomal introns: not only cut and paste.

Morello L, Breviario D - Curr. Genomics (2008)

Bottom Line: Furthermore, some introns also contain promoter sequences for alternative transcripts.Nevertheless, such regulatory roles do not require long conserved sequences, so that introns are relatively free to evolve faster than exons: this feature makes them important tools for evolutionary studies and provides the basis for the development of DNA molecular markers for polymorphisms detection.A survey of introns functions in the plant kingdom is presented.

View Article: PubMed Central - PubMed

Affiliation: Istituto Biologia e Biotecnologia Agraria, Via Bassini 15, 20133 Milano, Italy.

ABSTRACT
Spliceosomal introns in higher eukaryotes are present in a high percentage of protein coding genes and represent a high proportion of transcribed nuclear DNA. In the last fifteen years, a growing mass of data concerning functional roles carried out by such intervening sequences elevated them from a selfish burden carried over by the nucleus to important active regulatory elements. Introns mediate complex gene regulation via alternative splicing; they may act in cis as expression enhancers through IME (intron-mediated enhancement of gene expression) and in trans as negative regulators through the generation of intronic microRNA. Furthermore, some introns also contain promoter sequences for alternative transcripts. Nevertheless, such regulatory roles do not require long conserved sequences, so that introns are relatively free to evolve faster than exons: this feature makes them important tools for evolutionary studies and provides the basis for the development of DNA molecular markers for polymorphisms detection. A survey of introns functions in the plant kingdom is presented.

No MeSH data available.


Schematic representation of the two mechanisms by which AFE- containing transcripts are generated (see text).
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Figure 2: Schematic representation of the two mechanisms by which AFE- containing transcripts are generated (see text).

Mentions: A more recent work identified about 5-6% of AFE clusters in both rice and Arabidopsis [64]. Many of them produce proteins with alternative N-terminal regions but a significant proportion, 50% in rice and 19% in Arabidopsis, lead to transcriptional variants differing only for their 5’UTR. AFE may be produced by two mechanisms (Fig. 2): in the first (type I), the two first exons are mutually exclusive; in the second (type II), the first exon of an alternative mRNA, exon 1b in Fig. (2), falls internal to the other.


Plant spliceosomal introns: not only cut and paste.

Morello L, Breviario D - Curr. Genomics (2008)

Schematic representation of the two mechanisms by which AFE- containing transcripts are generated (see text).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2682935&req=5

Figure 2: Schematic representation of the two mechanisms by which AFE- containing transcripts are generated (see text).
Mentions: A more recent work identified about 5-6% of AFE clusters in both rice and Arabidopsis [64]. Many of them produce proteins with alternative N-terminal regions but a significant proportion, 50% in rice and 19% in Arabidopsis, lead to transcriptional variants differing only for their 5’UTR. AFE may be produced by two mechanisms (Fig. 2): in the first (type I), the two first exons are mutually exclusive; in the second (type II), the first exon of an alternative mRNA, exon 1b in Fig. (2), falls internal to the other.

Bottom Line: Furthermore, some introns also contain promoter sequences for alternative transcripts.Nevertheless, such regulatory roles do not require long conserved sequences, so that introns are relatively free to evolve faster than exons: this feature makes them important tools for evolutionary studies and provides the basis for the development of DNA molecular markers for polymorphisms detection.A survey of introns functions in the plant kingdom is presented.

View Article: PubMed Central - PubMed

Affiliation: Istituto Biologia e Biotecnologia Agraria, Via Bassini 15, 20133 Milano, Italy.

ABSTRACT
Spliceosomal introns in higher eukaryotes are present in a high percentage of protein coding genes and represent a high proportion of transcribed nuclear DNA. In the last fifteen years, a growing mass of data concerning functional roles carried out by such intervening sequences elevated them from a selfish burden carried over by the nucleus to important active regulatory elements. Introns mediate complex gene regulation via alternative splicing; they may act in cis as expression enhancers through IME (intron-mediated enhancement of gene expression) and in trans as negative regulators through the generation of intronic microRNA. Furthermore, some introns also contain promoter sequences for alternative transcripts. Nevertheless, such regulatory roles do not require long conserved sequences, so that introns are relatively free to evolve faster than exons: this feature makes them important tools for evolutionary studies and provides the basis for the development of DNA molecular markers for polymorphisms detection. A survey of introns functions in the plant kingdom is presented.

No MeSH data available.