ISSN:
1617-4623
Keywords:
Key words Maize
;
Mitochondria
;
RNA polymerase
;
Alternative splicing
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Single-subunit RNA polymerases belonging to the T3/T7 bacteriophage family are thought to be common throughout eukaryotes. We report the isolation and characterization of a nucleus-encoded single-subunit RNA polymerase gene from maize. This gene is highly homologous to other single-subunit RNA polymerase genes from Arabidopsis, Chenopodium, yeast and Neurospora crassa involved in organellar transcription. Genomic Southern analysis reveals 10 to 15 hybridising fragments, suggesting that maize contains a small gene family. The isolated gene contains 19 exons and its genomic structure is highly conserved when compared to the three Arabidopsis homologues. Unlike the case in Arabidopsis, intron-12 of the maize bacteriophage-type RNA polymerase gene is alternatively spliced. Quantitative RT-PCR revealed that the resultant alternatively spliced transcript represents approximately 21 to 26% of the total polymerase mRNA in maize coleoptiles. The orthologous wheat bacteriophage-type RNA polymerase is also alternatively spliced and the intron exhibits 78% identity to maize intron-12. The conservation in alternative splicing between wheat and maize and its absence from Arabidopsis suggest a functional requirement for the alternatively spliced product.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004380050867
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