the enzymes responsible for creating and metabo- 
lizing them can be assessed. 
As a by-product of the studies directed toward iso- 
lating the OCRL gene, Dr. Nussbaum and his col- 
leagues found, entirely by chance, the human gene 
hSNF2L. Although not involved in OCRL, this gene 
has interesting homologies to a number of previ- 
ously identified genes in yeast and Drosophila. 
SNF2/SWI2 and STHl from Saccharomyces cerevi- 
siae and brahma in Drosophila melanogaster rep- 
resent a class of transcription factors or cofactors 
termed "global" activators of transcription. The 
Snf2 and brahma proteins appear to exert their ef- 
fects on transcription as part of multifactor com- 
plexes and may serve as bridges between specific 
DNA-binding proteins and the transcriptional appa- 
ratus. The strong similarity between hSNF2L and 
these yeast and Drosophila genes suggests that the 
mammalian gene is part of an evolutionarily con- 
served family that has been implicated as global ac- 
tivators of transcription in yeast and fruit flies but 
whose function in vertebrates is unknown. The labo- 
ratory has begun to isolate and characterize the mu- 
rine and amphibian homologues of hSNF2L, in 
order to study the timing and tissue distribution of 
its expression and to create a deletion mutation of 
this gene in mice. 
Dr. Nussbaum is also Associate Professor of Hu- 
man Genetics, Pediatrics, and Internal Medicine 
at the University of Pennsylvania School of Medi- 
cine and Consultant in Genetics at the Children's 
Hospital of Philadelphia. 
Books and Chapters of Books 
Gelehrter, T., King, R., Ledbetter, D., and Nuss- 
baum, R.L. 1991. Molecular medicine and genet- 
ics. In Medical Knowledge Self-Assesment Pro- 
gram IX. Philadelphia, PA: American College of 
Physicians, pp 1-42. 
Articles 
Attree, O., Olivos, I.M., Okabe, I., Bailey, L.C., Nel- 
son, D.L., Lewis, R.A., Mclnnes, R.R., and Nuss- 
baum, R.L. 1992. The Lowe's oculocerebrorenal 
syndrome gene encodes a protein highly homolo- 
gous to inositol polyphosphate- 5 -phosphatase. 
Nature 358:239-242. 
Davies, K.E., Mandel, J.-L., Monaco, A.P., Nuss- 
baum, R.L., and Willard, H.F. 1991 . Report of the 
Committee on the Genetic Constitution of the X 
Chromosome (Human Gene Mapping 11). Cyto- 
gen Cell Genet 58:853-966. 
Lee, J.T., Murgia, A., Sosnoski, D.M., Olivos, I.M., 
and Nussbaum, R.L. 1992. Construction and 
characterization of a yeast artificial chromosome 
library for Xpter-Xq27.3: a systematic determina- 
tion of cocloning rate and X-chromosome repre- 
sentation. Genomics 12:526-533- 
Merry, D.E., Janne, P.A., Landers, J.E., Lewis, R.A., 
and Nussbaum, R.L. 1992. Isolation of a candi- 
date gene for choroideremia. Proc Natl Acad Sci 
USA 89:2135-2139. 
Okabe, I., Bailey, L.C., Attree, O.F., Srinivasan, S., 
Perkel, J.M., Laurent, B.C., Carlson, M., Nelson, 
D.L., and Nussbaum, R.L. 1992. Cloning of hu- 
man and bovine homologs of SNF2/SWI2, a global 
activator of transcription in yeast S. cerevisiae. 
Nucleic Acids Res 20:4649-4655. 
Puck, J.M., Stewart, C.C., and Nussbaum, R.L. 
1992. Maximum-likelihood analysis of human T- 
cell X chromosome inactivation patterns: normal 
women versus carriers of X-linked severe com- 
bined immunodeficiency. Am f Hum Genet 
50:742-748. 
Spielman, R.S., and Nussbaum, R.L. 1992. Dual de- 
velopments in diabetes. Nature Genet 1:82-83. 
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