Cytogenet. Cell Genet. 22: 570-572 (1978)
Assignment of the genes coding for pyrophosphatase and hexokinase-1 to mouse chromosome 10: implications for comparative gene mapping in man and mouse P.A. L alley ,1 U. F ranoce ,2 and J.D. M inna 1 ■NCI-VA Medical Oncology Branch, Veterans Administration Hospital, Washington, D.C., and 2Departmcnt of Pediatrics, University of California. San Diego, School of Medicine, La Jolla, Calif.
It is possible to generate somatic cell hybrids which preferentially lose the chromosomes of any desired species. Therefore, this parasexual technique, which has been used so successfully in mapping the human genome, can be utilized to investigate the linkage relationships of homo logous genes in several species. The data derived from such studies would help to determine which linkage groups have been conserved or disrupted during evolution. The genes coding for hexokinase-1 (HKi, E.C. 2.7.1.1), pyrophosphatase (inorganic) (PP, E.C. 3.6.1.1) and glutamic-oxaloacetic transaminase (soluble) (GOTs, E.C. 2.6.1.1) have been assigned to chromosome 10 in man.1 In the mouse, the gene coding for GOT-1 (homologous to human GOTs) is assigned to chromosome 19.2 Therefore, we have investigated the linkage relationships of mouse hexokinase-1 and inorganic pyro phosphatase to determine if the linkage group of HK-1, PP, and GOTs on human chromosome 10 is conserved in the mouse.
U.F. is supported by USPHS grant GM 21110 and by The National Foundation.
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Chinese hamster X mouse somatic cell hybrids segregating mouse chromosomes were isolated and expanded for enzyme and chromosome studies.* Starch-gel electrophoresis was used to visualize hexokinase activity in cell extracts employing a tris-EDTA-borate buffer, pH 8.6, as described.'1 Mouse HK-1 is readily distin guished from Chinese hamster hexokinase activity, which migrates more toward the anode. Mouse and Chinese hamster inorganic pyrophosphatase (PP) was separated employing a tris-EDTA-maleic acid)buffer system, pH 8.0, as described.1» Chinese hamster PP migrates faster toward the anode than mouse PP. In hybrids scored positive for mouse PP, a single heteropolymer is expressed, indicating that the enzyme is a dimer.
L alley et al.
571
Comparative mapping of gene loci
Table I. Assignment of inorganic pyrophosphatase (PP) and hexokinase-1 (HK-1) to mouse chromosome 10.» HK-1
TRIP-1
+
+
-f
—
-
—
Number of clones
PP
20 10
-L .
__
+
12
—
0
0 6
—
Chromosome 10
+ —
13 0
TRIP-1
HK-1
PP
0 7
+ 13 —
C
0
Thirty Chinese hamster X mouse primary hybrid clones were tested for the expression of PP, HK-1, and 22 other mouse enzymes sufficient to code for 12 of the 20 mouse chromosomes. The data presented in table I indicate that the genes coding for PP and HK-1 segregated concordantly with tripeptidase-1 (TRIP-1, homologous to human PEPB. E.C. 3.4.11.*), indicating that these three genes are linked. Recently, the gene coding for TRIP-1 was assigned to mouse chromosome 1(),a suggesting that Pp and HK-1 can also be assigned to chromosome 10. Chromosome and enzyme studies on 20 clones support this assignment. Chromosome 10 segregated concordantly with PP, HK-1 and TRIP-1 (table I). No exceptions were noted, and all other chromosomes segregated discordantly. The data presented here demonstrate that pyrophosphatase and hexo kinase-1 are syntenic in man and mouse. However, Got-1 (homologous to human GOTs) is not linked to Pp and Hk-1 in the mouse,- indicating a disruption of the syntenic group on human chromosome 10. The exact regional localization and genetic distances for these genes is not known in either species, indicating a need for complementary studies between somatic cell hybrid and sexual genetics. However, it is interesting to note that GOTs has been assigned to the distal portion of the long arm of human chromosome 10,” whereas PP and HK-1 are localized on the short
Downloaded by: Thomas Jefferson University Scott Library 147.140.27.100 - 8/24/2018 5:55:41 AM
» Gel electrophoresis for identifying the enzyme phenotypes was performed as described.-*.».8 Hoechst 33258 fluorescence and trypsin-Giemsa banding techniques were used to identify the chromosomes as described.1»
572
L alley et al.
Comparative mapping of gene loci
arm or proximal to the centromere on the long arm.7 Numerous chromo some rearrangements occurred during the divergent evolution of primates and rodents, resulting in quite different chromosome banding patterns. It will be interesting to see if high-resolution chromosome banding tech niques reveal homologies of chromosomal regions between man and mouse in chromosomes that contain homologous linkage groups. We gratefully acknowledge the excellent technical assistance of S. Stephenson, T. G regorio, M. Brown, and W. Moss.
Downloaded by: Thomas Jefferson University Scott Library 147.140.27.100 - 8/24/2018 5:55:41 AM
1 R uddle, F.H. and M eera K han, P.: Report of the committee on the genetic constitution of autosomes other than chromosomes 1, 2, and 6. Baltimore Con ference (1975), pp. 31-53. 2 Womack, J.E.: Linkage map of the mouse. Mouse News Lett. 55: 6 (1976). 3 M inna, J.D.; M arshall, T.H., and Schaffer-Berman, P.V.: Chinese hamster X mouse hybrid cells segregating mouse chromosomes and isozymes. Somat. Cell Genet. 1: 335-369 (1975). 4 Shows, T.B.: Somatic cell genetics of enzyme markers associated with three human linkage groups. In R.L. D avidson and F.F. de la C ruz, eds.: Somatic cell hybridization, pp. 15-26 (Raven Press, New York 1974). 5 H arris, H. and H opkinson, D.A.: Handbook of enzyme electrophoresis in human genetics (American Elsevier, New York 1976). 6 F rancke, U.; L ali.ey, P.A.; Moss, W.; I vy, J., and M inna, J.D.: Gene mapping in Mus inusculus by interspecific cell hybridization: assignment of the genes for tripeptidasc-1 to chromosome 10, dipeptidase-2 to chromosome 18, acid phos phatase-1 to chromosome 12, and adenylate kinase-1 to chromosome 2. Cytogenet. Cell Genet. 19: 57-84 (1977). 7 C hern, C.J.; M ellman, W.J., and C roce, C.M.: Localization of the structural locus for cytoplasmic glutamic-oxaloacetic transaminase to region q24—»-qtcr of human chromosome 10. Baltimore Conference (1975), pp. 108-110. 8 L alley, P.A.; Brown, J.A.; E ddy, R.L.; H aley, L.L.; Byers, M.G.; G oggin, A.P.. and Shows, T.B.: Human /5-glucuronidase: assignment of the structural gene to chromosome 7 using somatic cell hybrids. Biochem. Genet. 15: 367-381 (1977).
Assignment of the genes coding for pyrophosphatase and hexokinase-1 to mouse chromosome 10: implications for comparative gene mapping in man and mouse P.A. L alley ,1 U. F ranoce ,2 and J.D. M inna 1 ■NCI-VA Medical Oncology Branch, Veterans Administration Hospital, Washington, D.C., and 2Departmcnt of Pediatrics, University of California. San Diego, School of Medicine, La Jolla, Calif.
It is possible to generate somatic cell hybrids which preferentially lose the chromosomes of any desired species. Therefore, this parasexual technique, which has been used so successfully in mapping the human genome, can be utilized to investigate the linkage relationships of homo logous genes in several species. The data derived from such studies would help to determine which linkage groups have been conserved or disrupted during evolution. The genes coding for hexokinase-1 (HKi, E.C. 2.7.1.1), pyrophosphatase (inorganic) (PP, E.C. 3.6.1.1) and glutamic-oxaloacetic transaminase (soluble) (GOTs, E.C. 2.6.1.1) have been assigned to chromosome 10 in man.1 In the mouse, the gene coding for GOT-1 (homologous to human GOTs) is assigned to chromosome 19.2 Therefore, we have investigated the linkage relationships of mouse hexokinase-1 and inorganic pyro phosphatase to determine if the linkage group of HK-1, PP, and GOTs on human chromosome 10 is conserved in the mouse.
U.F. is supported by USPHS grant GM 21110 and by The National Foundation.
Downloaded by: Thomas Jefferson University Scott Library 147.140.27.100 - 8/24/2018 5:55:41 AM
Chinese hamster X mouse somatic cell hybrids segregating mouse chromosomes were isolated and expanded for enzyme and chromosome studies.* Starch-gel electrophoresis was used to visualize hexokinase activity in cell extracts employing a tris-EDTA-borate buffer, pH 8.6, as described.'1 Mouse HK-1 is readily distin guished from Chinese hamster hexokinase activity, which migrates more toward the anode. Mouse and Chinese hamster inorganic pyrophosphatase (PP) was separated employing a tris-EDTA-maleic acid)buffer system, pH 8.0, as described.1» Chinese hamster PP migrates faster toward the anode than mouse PP. In hybrids scored positive for mouse PP, a single heteropolymer is expressed, indicating that the enzyme is a dimer.
L alley et al.
571
Comparative mapping of gene loci
Table I. Assignment of inorganic pyrophosphatase (PP) and hexokinase-1 (HK-1) to mouse chromosome 10.» HK-1
TRIP-1
+
+
-f
—
-
—
Number of clones
PP
20 10
-L .
__
+
12
—
0
0 6
—
Chromosome 10
+ —
13 0
TRIP-1
HK-1
PP
0 7
+ 13 —
C
0
Thirty Chinese hamster X mouse primary hybrid clones were tested for the expression of PP, HK-1, and 22 other mouse enzymes sufficient to code for 12 of the 20 mouse chromosomes. The data presented in table I indicate that the genes coding for PP and HK-1 segregated concordantly with tripeptidase-1 (TRIP-1, homologous to human PEPB. E.C. 3.4.11.*), indicating that these three genes are linked. Recently, the gene coding for TRIP-1 was assigned to mouse chromosome 1(),a suggesting that Pp and HK-1 can also be assigned to chromosome 10. Chromosome and enzyme studies on 20 clones support this assignment. Chromosome 10 segregated concordantly with PP, HK-1 and TRIP-1 (table I). No exceptions were noted, and all other chromosomes segregated discordantly. The data presented here demonstrate that pyrophosphatase and hexo kinase-1 are syntenic in man and mouse. However, Got-1 (homologous to human GOTs) is not linked to Pp and Hk-1 in the mouse,- indicating a disruption of the syntenic group on human chromosome 10. The exact regional localization and genetic distances for these genes is not known in either species, indicating a need for complementary studies between somatic cell hybrid and sexual genetics. However, it is interesting to note that GOTs has been assigned to the distal portion of the long arm of human chromosome 10,” whereas PP and HK-1 are localized on the short
Downloaded by: Thomas Jefferson University Scott Library 147.140.27.100 - 8/24/2018 5:55:41 AM
» Gel electrophoresis for identifying the enzyme phenotypes was performed as described.-*.».8 Hoechst 33258 fluorescence and trypsin-Giemsa banding techniques were used to identify the chromosomes as described.1»
572
L alley et al.
Comparative mapping of gene loci
arm or proximal to the centromere on the long arm.7 Numerous chromo some rearrangements occurred during the divergent evolution of primates and rodents, resulting in quite different chromosome banding patterns. It will be interesting to see if high-resolution chromosome banding tech niques reveal homologies of chromosomal regions between man and mouse in chromosomes that contain homologous linkage groups. We gratefully acknowledge the excellent technical assistance of S. Stephenson, T. G regorio, M. Brown, and W. Moss.
Downloaded by: Thomas Jefferson University Scott Library 147.140.27.100 - 8/24/2018 5:55:41 AM
1 R uddle, F.H. and M eera K han, P.: Report of the committee on the genetic constitution of autosomes other than chromosomes 1, 2, and 6. Baltimore Con ference (1975), pp. 31-53. 2 Womack, J.E.: Linkage map of the mouse. Mouse News Lett. 55: 6 (1976). 3 M inna, J.D.; M arshall, T.H., and Schaffer-Berman, P.V.: Chinese hamster X mouse hybrid cells segregating mouse chromosomes and isozymes. Somat. Cell Genet. 1: 335-369 (1975). 4 Shows, T.B.: Somatic cell genetics of enzyme markers associated with three human linkage groups. In R.L. D avidson and F.F. de la C ruz, eds.: Somatic cell hybridization, pp. 15-26 (Raven Press, New York 1974). 5 H arris, H. and H opkinson, D.A.: Handbook of enzyme electrophoresis in human genetics (American Elsevier, New York 1976). 6 F rancke, U.; L ali.ey, P.A.; Moss, W.; I vy, J., and M inna, J.D.: Gene mapping in Mus inusculus by interspecific cell hybridization: assignment of the genes for tripeptidasc-1 to chromosome 10, dipeptidase-2 to chromosome 18, acid phos phatase-1 to chromosome 12, and adenylate kinase-1 to chromosome 2. Cytogenet. Cell Genet. 19: 57-84 (1977). 7 C hern, C.J.; M ellman, W.J., and C roce, C.M.: Localization of the structural locus for cytoplasmic glutamic-oxaloacetic transaminase to region q24—»-qtcr of human chromosome 10. Baltimore Conference (1975), pp. 108-110. 8 L alley, P.A.; Brown, J.A.; E ddy, R.L.; H aley, L.L.; Byers, M.G.; G oggin, A.P.. and Shows, T.B.: Human /5-glucuronidase: assignment of the structural gene to chromosome 7 using somatic cell hybrids. Biochem. Genet. 15: 367-381 (1977).
