THE TRNA(TYR) MULTIGENE FAMILY OF TRITICUM-AESTIVUM - GENOME ORGANIZATION, SEQUENCE ANALYSES AND MATURATION OF INTRON-CONTAINING PRE-TRANSFER-RNAS IN WHEAT-GERM EXTRACT

Southern analysis of Triticum DNA has revealed that nuclear tRNA(Tyr) genes are dispersed at a minimum of 16 loci in the genome. We have iso lated six independent tRNA(Tyr) genes from a Triticum aestivum library in addition to three known members of the Triticum tRNA(Tyr) family. Four of the sequenced tRNA(Tyr) genes code for Triticum tRNA(1)(Tyr) a nd two code for tRNA(2)(Tyr). Three genes encode tRNAs(Tyr) which carr y one or two nucleotide substitutions as compared to the conventional genes. The nine Triticum tRNA(Tyr) genes possess highly conserved intr on sequences ranging in size from 12 to 14 nucleotides. A common secon dary intron structure with the 5' and 3' splice site loops separated b y five base pairs can be formed by all pre-tRNAs(Tyr) which are effici ently spliced in the homologous wheat germ extract.