This biochemical heterogeneity in Qa-2 molecules 
is detected after removal of N-linked oligosaccha- 
rides from cell surface forms or by analysis of pre- 
cursor intracellular forms of Qa-2. Gene trans- 
fection studies from this and other laboratories and 
amino-terminal amino acid sequence analyses of 
Qa-2 -reactive proteins have documented that at 
least two genes, Q7 and Q9, are normally expressed 
in cells and encode Qa-2 antigens. Biochemical 
studies on the Q region gene transfectants and 
Northern blot analyses indicate that the Q7 gene 
encodes the Qa-2 molecules that express the Qa-6 
determinant. Thus those strains that are Qa-2 ^6"*^ 
express both the Q7 and Q9 genes, whereas those 
strains that are Qa-2 '"^6" express only the Q9 gene. 
The Qa-2 cell surface molecules, like several 
other antigens, are not integral membrane proteins 
but are attached to the cell surface by a glycolipid 
anchor. Many of these glycolipid-attached proteins 
have the capacity to induce cell activation and pro- 
liferation after the binding of specific antibodies to 
these proteins. Dr. Cook's laboratory has devel- 
PUBLICATIONS 
oped a panel of anti-Qa-2 -specific monoclonal an- 
tibodies and examined them for the ability to acti- 
vate Qa-2^ cells. Several can induce cell proliferation 
when a second accessory signal is also added. The 
extent of cell activation induced by these anti-Qa-2 
monoclonal antibodies seems to correlate with the 
cell surface density of Qa-2; high levels of Qa-2 lead 
to a more vigorous proliferative response. These 
data suggest that the Qa-2 antigens may play a role 
in normal cellular activation processes. Qa-2 may 
serve an accessory role in the normal T cell receptor 
antigen-specific activation pathway or may serve as 
a receptor for cell-associated or soluble ligands im- 
portant in novel activation or cell-to-cell interaction 
pathways. Experiments are in progress to character- 
ize the regions of the Qa-2 molecule and accessory 
signals that are essential for inducing cell activation 
as well as the intracellular events and second mes- 
sengers involved in the Qa-2 activation pathway. 
Dr. Cook is Associate Professor of Microbiology 
and Immunology at Baylor College of Medicine. 
Articles 
Boggs, B.A., Minotti, A.M., Loeb, L.M., Cook, R., and Cabral, F. 1988. Mutations affecting assembly of 
(3-tubulin localize to a region near the carboxy terminus. J Biol Chem 263:14566-14573- 
Bramucci, M., Roll, D., Cook, R., and Durban, E. 1989- Identification of consensus epitope structures ex- 
pressed in recombinant DNA libraries. Mol Immunol 26:741-748. 
Durban, E., Bramucci, M., and Cook, R. 1988. Partial amino acid sequence of rat topoisomerase I. Compari- 
son with the predicted sequences for the human and yeast enzymes. Biochem Biophys Res Commun 
154:358-364. 
Hertzberg, E.L., Disher, R.M., Tiller, A.A., Zhou, Y, and Cook, R.G. 1988. Topology of the Af^ 27,000 liver gap 
junction protein. Cytoplasmic localization of amino- and carboxyl termini and a hydrophilic domain which 
is protease-hypersensitive. J Biol Chem 263:19105-19111. 
Johnston, G.I., Cook, R.G., and McEver, R.P 1989. Cloning of GMP-140, a granule membrane protein of 
platelets and endothelium: sequence similarity to proteins involved in cell adhesion and inflammation. 
Ce// 56: 1033-1044. 
Lin, R., Leone, J.W , Cook, R.G. , and Allis, CD. 1989. Antibodies specific to acetylated histones document 
the existence of deposition- and transcription-related histone acetylation in Tetrahymena. J Cell Biol 
108:1577-1588. 
MoUick, J.A., Cook, R.G., and Rich, R.R. 1989. Class II MHC molecules are specific receptors ior Staphylococ- 
cus enterotoxin A. Science 244:817-820. 
Norris, S.J., Charon, N.W, Cook, R.G. , Fuentes, M.D., and Limberger, R.J. 1988. Antigenic relatedness and 
N-terminal sequence homology define two classes of periplasmic flagellar proteins of Treponema pal- 
lidum suhsp. pallidum and Treponema phagedenis. J Bacteriol 170:4072-4082. 
Ono, T, Slaughter, G.R., Cook, R.G., and Means, A.R. 1989. Molecular cloning sequence and distribution of 
rat calspermin, a high affinity calmodulin-binding protein. J Biol Chem 264:2081-2087. 
Continued 
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