__~_] 996 PROGRAM Twenty-Second Annual
9:00 a.m. Registration and Coffee - Room 137, tains of the cleavage site and a four-nucleotide tlght turn
Chemistry-Physics Building that resembles the "U-turn" in the tRNA antiloop. Domain
II is a double stranded helix containin four noncanonical
9:30 a.m. Welcome by Dr. Fitzgerald Bramwell, Vice base pairs. Numerous biochemical expiriments have shown Ch em i st
mgtnsgigggrhxgsxufgmm that the most of the nucleotides in both domains are essen- ry
139 Chemistry-Physics Building tial for full activity of the hammerhead. Biochemical and
' crystallographic experiments also indicate that both domains &
9:35 a.m. Introductory Remarks , Dr. Allan contain one or more divalent metal ions bound to specic
Buttereld. 0mm of Kentuc sites. The general goal is to understand how these two 0-
ty ky mains collaborate to cause the appraidmately IDs-fold en- MOIGCUIGr
9:40 a.m. Dr. Phillip A. Sharp. Massachusetts hancement of the rate of chemical cleavage. Our laboratory .
Institute Of Technology has developed a ldnetic framework to analyze the properties BIOlogy
RNA Splicing of hammerheads with dened functional group substitutions
The genes of mammals contain an average of 10 introns at unique sites. The current focus is on examining the cleav-
whose length can extend 100.000 nucleotides. Precise exci- age s1te nucleotide which forms a tertiary interaction that
sion of these introns is essential for gene expression. The appears to prevent the structure from adopting an active
sequence specicity for intron excision can be considered in conguration. We will also present experiments examining
two classes. microspecicity directing the chemistry of the the role of various metal ion binding sites in the hammer-
splicing process, and macrospecicity dening the exon se head.
quences to be joined during splicing. The conserved con 11:20 gm, Discussion
sensus sequences at the boundary of introns and at the
branch site are the microspecicity. Interestingly the se- 11:30 mm. Dr. James R. Williamson. Massachusetts
quences at the 5' splice site are recognized twice during the Institute of Technology
splicing process, once by U1 snRNP and subsequently by MtddimensionalI-IeteronuclearNMRStudies
U6 snRNA and other components of the spliceosome. Dur- of RM ' POte'" Interactions to HIV
ing reactions in vitro it is possible to bypass the U1 recogni- Formation of RNA-protein interactions is important for
tion during formation of a spliceosome. By inference the regulation of all levels of gene expression, including tran-
utilization of this bypass pathway couldbeimportant inregu- scription. mRNA processing. and translation. In order to established in the memory Of
lation invivo. Surprisingly, the U1 snRNP independent path- understand the structural basis for the interaction of RNA Anna S Naff
way for splicing is probably also not dependent upon the with proteins, we are studying RNA-protein and RNA-pep- '
activity of another splicing factor U2AF. A subclass of prO- tide complexes using multidimensional heteronuclear NMR '
teins that regulate RNA splicing contain a diamino repeti- spectroscopy. The rst step in the structure determination -----
tive sequence. Ser-Arg (SR)- This repetitive subdomain is is to prepare a minimal RNA-protein complex that is suit- .
partially phosphorylated in vivo and is thought to associate able for NMR studies. This usually entails the detailed bio- Bl 0 Ch emist Of RN A
with other SR domains in mediating formation 0f SpiiCing chemical characterization of the complex. The second step TY
complexes. Recent experiments suggest that there is an is to apply NMR methods to obtain distance and dihedral
extended family of proteins with SR subdomains. These information that permits the structure to be determined. _
proteins are concentrated in subregions of the nucleus where Two different RNA-protein complexes will be presented. First. a
RNA splicing occurs. Some members of the SR family are the ribosomal Sl5rRNA complex will be described to illus- 0
best pictured as lattice proteins which associate with mul- trate the biochemical characterization Of an RNA-protein E >5 C? SPEAKERS
tiple SR proteins bound to RNA. It is proposed that some complex. Second. the structure of the HIV RevRev Respon 5 M 8 Phi. A Sh
aspects of both nuclear structure and gene structure are sive Element (RRE) complexwillbedescribed, as determined a B In , . I 'p ' arp
related to the activities of SR proteins in RNA splicing. by NMR spectroscopy. In both of these complexes. the RNA 2-." E S Olke C. Uhlenbeck
10:25 a.m. Discussion adopts a particular structure that is critical for recognition 8 S2 >4 James R. Williamson
by proteins. By studying a series of complexes, we hope to O 9. M
10:35 a.m. Dr. Olke C. Uhlenbeck. University of begin to understand how the unusual structures that abound *5 o .
Colorado in RNA contribute to the specic recognition by proteins. a.) JED 8
Mechanisms OfleHwnmerheadRibozyme 12:15 p.m. Discussion .2 g 55 Monday, April 15, I996
The hammerhead ribozyme is a small RNA motif that 12:30 p.m. Buffet Lunch. Faculty Club (Please return 9-. -> a
undergoes autolytic cleavage at a unique site to give 5' hy- registration form by April 8, 1996 for 0-) a a.) _
dtrlouxytluand f2th3' 1::wa plosghate tennmi'fu'lhtlzliecgrary reservations. Cost $10.00 to be paid at O D "I Department Of Chemlstry
s c e o e ammer ea consists o ee A 'ces re smon. - '
joining in a central core of l 1 nucleotides. Two recent x-ray gi ) _ UniverSIty Of KentUCKy
crystal structures of the hammerhead reveal that the core 2:30 p.m. Discussion with Graduate Students -  Lexmgton, KentUCKy 40506'0055
consists of two different folding domains. Domain I con- Room 137. Chemistry-Physics Building