CHARACTERIZATION OF A NUCLEAR MALE STERILE GENE ISOLATED BY TRANSPOSONTAGGING

WE PROPOSE TO USE TRANSPOSON-TAGGING TO ISOLATE NUCLEAR MALESTERILE GENES FROM CORN. WE HAVE GENERATED 21 MALE STERILE MUTANTS IN LINES CARRYING THE TRANSPOSABLE ELEMENTS AC OR SPM. SOME OF THESE MUTANTS WERE MOST LIKELY GENERATED BY THE INSERTION OF AN AC OR SPM ELEMENT. GENETIC EVIDENCE SUGGESTS THAT IN AT LEAST ONE CASE AC HAS TAGGED A MALE STERILE GENE. WE HAVE USED AC AS A PROBE TO CLONE THIS ELEMENT AND THE DNA FLANKING IT. DURING PHASE I WE WILL THEN USE FLANKING SEQUENCES TO CLONE THE MALE STERILE ALLELEAND WE WILL CHARACTERIZE THE STRUCTURE AND EXPRESSION OF THIS GENE AS A PRELIMINARY STEP TO ISOLATING OTHER MALE STERIL MUTANTS, WE WILL ALSO DETERMINE WHETHER AC OR SPM HAS TRANSPOSED IN ANY OF THE OTHER MUTANTS. THESE TRANSPOSITIONAL EVENTS CAN BE DETECTED AS NOVEL RESTRICTION FRAGMENTS HYBRIDIZING TO AC OR SPM-SPECIFIC PROBES. OVER 17 NUCLEAR MS GENES HAVE BEEN IDENTIFIED IN MAIZE. THEDEVELOPMENTAL SEQUENCE OF MICROSPOROGENESIS BREAKDOWN HAS BEEN STUDIED IN A NUMBER OF CASES, BUT NO INFORMATION IS YETAVAILABLE ON THE CAUSES UNDERLYING MALE STERILITY. ISOLATION AND CHARACTERIZATION OF MUCLEAR MS GENES WILL ENABLE US TO IDENTIFY THE PRIMARY GENE PRODUCTS RESPONSIBLE FOR MALE FERTILITY, WHICH SHOULD SERVE AS A HANDLE TOWARDS ULTIMATELY UNDERSTANDING THE MOLECULAR EVENTS INVOLVED IN MICROSPOROGENESIS. IN ADDITION, ISOLATION OF A MS GENE MAY ALLOW US TO UTILIZE NUCLEAR MALE STERILITY.