Structure and expression of a CTP: phosphocholine cytidylyltransferase gene from Arabidopsis thaliana.

A genomic clone, which includes the CTP: phosphocholine cytidylyltransferase (CCT) open reading frame and its 5'- and 3'- flanking non-coding regions, has been isolated from Arabidopsis thaliana and sequenced. The CCT gene is approximately 3.0 kb in length and contains 8 exons interrupted by 7 introns, which range from 74 to 626 nucleotides. All nucleotide sequences for the intron 3' splice sites are consistent with the consensus AG sequence of plant pre-mRNA processing, while the major GT consensus sequence for the 5' splice site is conserved in 5 of 7 introns. Introns 5 and 6 have a minor GC consensus sequence instead. In the 5'-flanking region there are two sequences related to a cold-responsive element found in the cold-inducible promoter of the A. thaliana cor15a gene, plus one gibberellin-response element. The results from reverse transcriptase-PCR indicate that the expression of A. thaliana CCT is regulated by temperature. The expression level of CCT increased after a 30-min treatment at 5 degrees C. When the plants were returned to 22 degrees C, the expression of CCT also decreased to the original level.