Phenylalanine ammonia-lyase gene structure, expression, and evolution in Nicotiana

被引:98
作者
FukasawaAkada, T
Kung, SD
Watson, JC
机构
[1] INDIANA UNIV PURDUE UNIV, DEPT BIOL, INDIANAPOLIS, IN 46202 USA
[2] UNIV MARYLAND, DEPT PLANT BIOL, COLLEGE PK, MD 20742 USA
[3] UNIV MARYLAND, AGR BIOTECHNOL CTR, COLLEGE PK, MD 20742 USA
[4] HONG KONG UNIV SCI & TECHNOL, DEPT BIOL, KOWLOON, HONG KONG
关键词
developmental regulation; gene expression; gene family; phenylalanine ammonia-lyase; tobacco; wound response;
D O I
10.1007/BF00019006
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Phenylalanine ammonia-lyase (PAL) catalyzes the first reaction in the general phenylpropanoid pathway leading to the production of phenolic compounds with a significant range of biological functions. A PAL gene we designated gPAL1, cloned from tobacco, consists of two exons separated by an intron of 1932 bp. Exon I, 398 bp, and exon II, 1747 bp, together encode a polypeptide of 715 amino acids. A putative TATA box and polyadenylation signal are found 144 bp upstream of the initiation codon and 193 bp downstream from the stop codon, respectively. Using various parts of gPAL1 as probes, genomic Southern blots indicated the presence of a small family of PAL genes in the tobacco genome that can be divided into two distinct subfamilies, one consisting of pal1 and pal2 and another of pal3 and pal4. Comparative genomic blot analysis of progenitor species (Nicotiana tomentosiformis and N. sylvestris) indicated that each species contains one PAL gene from each of the subfamilies, suggesting that pall and pal3 (or pal2 and pal4) diverged prior to the evolution of N. tabacum. Expression of the PAL gene family was examined using RNA gel blots. PAL transcript levels were significantly higher in flowers and roots than in leaves and stems of mature plants. PAL transcripts accumulate differentially during flower and leaf maturation in that mRNA levels decline during flower maturation but increase during leaf maturation. In leaves, PAL transcripts rapidly accumulated after wounding.
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页码:711 / 722
页数:12
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