BRIEF REPORTS 479 more recent localization of GNASl to the distal long arm of chromosome 20 (Gejman et al., 1991; Baa et al., 1991). The localization of the GNASl gene locus to human chromosome 20q13.2 * 13.3 now permits assignment of the disorder AH0 to this region. We predict that character- ization of defects within the GNASl gene locus in man will further broaden our understanding of the function of this gene, of genes with which it is associated, and of the molecu- lar events of neurohormonal signal transduction from cell surface receptors to adenylyl cyclase. 1. 2. 3. 4. 5. 6. 9. 10. 11. 12. 13. REFERENCES ASHLEY, P. L., ELLISON, J., SULLIVAN, K. A., BOURNJZ, H. R., AND COX, D. R. (1987). Chromosomal assignment of the mu- rine Gi alpha and Gs alpha genes: Implications for the obese mouse. J. Biol. Chem. 262: X299-15301. BLATT, C., EVERSOLE-CIRE, P., COHN, V. H., ZOLLMAN, S., FOURNIER, R. E. K., MOHANDA& L. T., NESB~, M., LUGO, T., JONES, D. T., REED, R. R., WEINER, L. P., SPARKE% R. S., AND SIMON, M. I. (1988). Chromosomal localization of genes encoding guanine nucleotide-binding protein subunits in mouse and human. Proc. Natl. Acad. Sci. USA 86: 7642-7646. BOURNE, H, R., SANDERS, D. A., AND MCCORMICK, F. (1990). The GTPase superfamily: A conserved switch for diverse cell functions. Nature 343: 125-132. GEJMAN, P. V., WEINSTEIN, L. S., MARTINEZ, M., SPIEGEL, A. M., CAO, Q., HSIEH, W.-T., HOEHE, M. R., AND GERSHON, E. S. (1991). Genetic mapping of the Gs-a subunit gene (GNASl) to the distal long arm of chromosome 20 using a polymorphism detected by denaturing gradient gel electropho- resis. Genomics 9~ 782-783. HAYASHI, S., GILLAM, I. C., DELANEY, A. D., AND TENER, G. M. (1978). Acetylation of chromosome squashes of Dro- sophilu melanogaster decreases the background in autoradio- graphs from hybridization with [‘=I]-labeled RNA. J. Histo- them. Cytochem. 26: 677-679. KOZASA, T., ITOH, H., TSUKAMOTO, T., AND KUIRO, Y. (1933). Isolation and characterization of the human Gsa gene. Proc. Natl. Acad. Sci. USA 85: 2081-2085. LANDIS, C. A., MASTERS, S. B., SPADA, A., PACE, A. M., BOURNE, H. R., AND VALLAR, L. (1989). GTPase inhibiting mutations activate the a chain of Gs and stimulate adenylyl cyclase in human pituitary tumors. Nature 340: 692-696. MODI, W. S., NASH, W. G., FERRARI, A. C., AND O’BRIEN, S. J. (1987). Cytogenetic methodologies for gene mapping and comparative analyses in mammalian cell culture systems. Gene Anal. Tech. 4: 75-85. PAT-IYZN, J. L., JOHNS, D. R., VALLE, D. G., EIL, C., GRUP- PUSO, P. A., STEELE, G., SMALLWOOD, P. M., AND tiNE, M. A. (1990). Mutation in the gene encoding the stimulatory G protein of adenylyl cyclase in Albright’s hereditary osteo- dystrophy. N. Engl. J. Med. 322: 1412-1419. RAO, V. V. N., SCHN~GER, S., AND HANSMANN, I. (1991). G protein G,cy (GNASl), the probable candidate gene for Al- bright hereditary osteodystrophy, is assigned to human chro- mosome 2Oq12-q13.2. Gerwmics 10: 257-261. WEINSTEIN, L. S., GEJMAN, P. V., FRIEDMAN, E., KADOWAKI, T., COLLINS, R. M., GERSHON, E. S., AND SPIEGEL, A. M. (1990). Mutations of the G,cY-subunit gene in Albright heredi- tary osteodystrophy detected by denaturing gradient gel elec- trophoresis. Proc. Natl. Acad. Sci. USA 87: 8287-8290. Assignment of Secretogranin I Locus to Mouse Chromosome 2 by in Situ Hybridization and Interspecific Backcross Analysis’ Nancy A. Jenkins,*-* M.-Genevieve Mattei, t Debra J. Gilbert,* Christian G. Linard,S Majambu Mbikay,+ Michel Chretien,# and Neal G. Copeland* *Mammalian Genetics Laboratory, ABL-Basic Research Program, NC/-Frederick Cancer Research and Development Center, Frederick, Maryland 2 1702; tlnserm U.242. Centre de G&tique Medicale, H6pital d’Enfants de la Timone, F- 13385 Marseille Cedex 5, France; and Uaboratoire 1. A. de S&e de Neuroendocrinologie Mol&ulaire, lnstitut de Recherches Cliniques de Montreal, Qut?bec, Canada H2W 1R7 (affiliated with lJniversit6 de Montreal) Received March 6, 1991; revised June 4, 1991 Secretogranin I (Scg-1), also called chromogranin B, be- longs to a family of acidic protein markers found in many endocrine and neuronal cells (reviewed in Angeletti, 1986). Scg-1 is particularly abundant in the pituitary and the adre- nal medulla. Its biological function is unknown, but, like the other members of the secretogranin family, it may be involved in sorting and packaging pro-hormones and pro- neuropeptides into secretory granules, as well as in modulat- ing their processing. We have recently cloned the cDNA for mouse Scg-1 (Linard et al., 1990). To further characterize the Scg-1 locus, we determined the mouse chromosomal lo- cation by in situ hybridization and interspecific backcross analysis. In situ hybridization experiments (Mattei et al., 1985) were carried out using metaphase spreads from a WMP male mouse (Bonhomme and G&net, 1989), in which all autosomes except 19 were in the form of metacentric Rob- ertsonian translocations (a gift from J. L. Guknet, Pasteur Institute, Paris, France) and a recombinant Bluescript plasmid containing a mouse Scg-1 insert of 2.3 kb (Linard et aZ., 1990), which was labeled by nick translation, as a probe. In the 100 metaphase cells examined, there were 186 silver grains associated with chromosomes and 68 of these (36.5%) were located on chromosome 2. The distribution of chromosome 2-associated grains was not random: 76.4% of them (52/68) mapped to the [F-G] region. This chromo- somal location was further refined by interspecific back- cross analysis. Interspecific backcross progeny were gener- ated by mating (C57BL/6J X Mus spretus)F, females X C57BL/6J males as described (Copeland and Jenkins, 1991). C57BL/6J and M. spretw DNAs were digested with several enzymes and analyzed by Southern blot hybridiza- tion (Siracusa et al., 1990) for informative restriction frag- 1 The U.S. Government’s right to retain a nonexclusive royalty- free license in and to the copyright covering this paper, for govem- mental purposes, is acknowledged. 2 To whom correspondence should be addressed. GENOMICS 11,479-480 (1991) 03&3-7543/91$3.00 Copyright 0 1991 by Academic Press, Inc. All rights of reproduction in any form reserved.