r c U 2g . . 3 (i) a Fifth Annual Symposmm on (Q '1 :0- 8:30 CoffeeCF Room 137 o i- 3 .3 < g 9:00 Welcome and IntroductionCF Room 139 5 9h '* - 7s 9. 9:15 STRUCTURE AND EXPRESSION OF INTERVENING SE- 8 g 0 QUENCESINEUCARYOTIC GENOMES on a $- CHEMISTRY Dr. Beniamin Lewin 0~ (,2 3 < a The recent discovery of interruptions in eucaryotic genes has Q and made it necessary to discard the concept of the gene as a contiguous length of DNA that is colinear with its product. Intervening sequences have been characterized in nuclear MOLECULAR and organelle genes of many eucaryotic species; their locations in related genes may show their origin to be distant BIOLOGY in evolution. The intervening sequences are transcribed but are spliced out of the primary transcript to produce a messenger RNA whose sequence is colinear with protein. In instances in which several intervening sequences must be established in memory of removed, discrete intermediate precursors may be found. This ' provides a new mechanism for the processing of giant nuclear ANNA S~ NAFF RNA. Alternative pathways of RNA splicing exist in some viral , . systems, so that overlapping products are generated from a single length of DNA. Transposition of sequences in cellular DNA has been found in certain situations. The genetic im- plications of this organization will be discussed. Interrupted Genes 10:20 Discussion and Coffee Break and RNA Splicing 10:40 ROLE OF RNA PROCESSING IN THE SYNTHESIS OF mRNAs Dr. Phillip A. Sharp The structure of mRNAs of viruses of animal cells has shown that RNA processing plays a critical role in the expression of genetic information in these systems. In general, several Speakers mRNAs are processed by RNA splicing from one transcription . ' , unit and these RNA species have similar sequences at both Dr Benlamin Lewm termini. The time course of synthesis and phenotypes of RNA Dr. Phillip A. Sharp synthesis in mutant-infected cells suggests that RNA Splicing can be regulated. These data will be discussed in terms of our current understanding of the biochemistry of RNA splicing and the sequence of the RNA products. The first step in further defining the components involved in excising intervening sequences and iaining RNA sequences 3 APRIL 23' 979 coding for a polypeptide is to develop an in vitro system 5 Z . . . . . . >< 1:, capable of carrying out this reaction. An in vttro system which -u i 70 synthesizes the correct 5 and 3 termini for adenovirus RNA 93 G) .C 2 has been developed. This will be discussed in terms of a gal _U l : hypothetical pathway for synthesis of mammalian mRNAs. l .2 > 8 0 Z 7: U 1); a Department of Chemistry :45 Discussion _O m > > . . m E a Z UniverSIty of Kentucky c m K Lexington, Kentucky 40506 n > 7 :l . -< 0 Z