title: Functional characterisation of an intron retaining K(+) transporter of barley reveals intron-mediated alternate splicing.
abstract: Intron retention in transcripts and the presence of 5' and 3' splice sites within these introns mediate alternate splicing, which is widely observed in animals and plants. Here, functional characterisation of the K(+) transporter, HvHKT2;1, with stably retained introns from barley (Hordeum vulgare) in yeast (Saccharomyces cerevisiae), and transcript profiling in yeast and transgenic tobacco (Nicotiana tabacum) is presented. Expression of intron-retaining HvHKT2;1 cDNA (HvHKT2;1-i) in trk1, trk2 yeast strain defective in K(+) uptake restored growth in medium containing hygromycin in the presence of different concentrations of K(+) and mediated hypersensitivity to Na(+) . HvHKT2;1-i produces multiple transcripts via alternate splicing of two regular introns and three exons in different compositions. HKT isoforms with retained introns and exon skipping variants were detected in relative expression analysis of (i) HvHKT2;1-i in barley under native conditions, (ii) in transgenic tobacco plants constitutively expressing HvHKT2;1-i, and (iii) in trk1, trk2 yeast expressing HvHKT2;1-i under control of an inducible promoter. Mixed proportions of three HKT transcripts: HvHKT2;1-e (first exon region), HvHKT2;1-i1 (first intron) and HvHKT2;1-i2 (second intron) were observed. The variation in transcript accumulation in response to changing K(+) and Na(+) concentrations was observed in both heterologous and plant systems. These findings suggest a link between intron-retaining transcripts and different splice variants to ion homeostasis, and their possible role in salt stress.
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.|Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan.
authors: K
authors: K
authors: Shahzad
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.|Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan.
authors: M
authors: M
authors: Rauf
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
authors: M
authors: M
authors: Ahmed
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
authors: Z A
authors: ZA
authors: Malik
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
authors: I
authors: I
authors: Habib
authors: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
authors: Z
authors: Z
authors: Ahmed
authors: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
authors: K
authors: K
authors: Mahmood
authors: Agricultural Biotechnology Laboratory, Department of Plant Science, University of Connecticut, Storrs, CT, USA.
authors: R
authors: R
authors: Ali
authors: International Centre for Biosaline Agriculture (ICBA), Dubai, UAE.
authors: K
authors: K
authors: Masmoudi
authors: Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors: F
authors: F
authors: Lemtiri-Chlieh
authors: Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors: C
authors: C
authors: Gehring
authors: Agricultural Biotechnology Laboratory, Department of Plant Science, University of Connecticut, Storrs, CT, USA.
authors: G A
authors: GA
authors: Berkowitz
authors: National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
authors: N A
authors: NA
authors: Saeed
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011188:Potassium / Q000378:metabolism; D020033:Protein Isoforms; D022821:RNA Splice Sites / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; D022821:RNA Splice Sites; D012964:Sodium; D011188:Potassium
keywords: Alternate splicing; HvHKT2; functional complementation; intron retention; transcriptional gene regulation; transporters and channels