The methylation status of a mouse metallothionein-I/human transthyretin fusion gene was studied during gametogenesis in transgenic mice. In the adult tissues of this mouse line, the promoter region of the transgene on chromosome 11 is methylated when it is maternally inherited and undermethylated when it is paternally inherited. Germ cells from various developmental stages of gametogenesis were isolated, and their DNAs were assayed using methylation-sensitive restriction endonucleases and the polymerase chain reaction. Only low to nonexistent levels of transgene methylation were detected in germ cells from 14.5-day-old male and female fetuses irrespective of the parental origin of the transgene. This undermethylated state persisted in oocytes from newborn females as well as in testicular spermatogenic cells and sperm. By contrast, the transgene promoter was completely methylated in fully grown oocytes arrested at the first meiotic prophase. The endogenous metallothionein-I gene promoter, located on a different chromosome, remained undermethylated at all stages examined, consistent with previous findings reported for a typical CpG island. Taken together, the results suggest that parental-specific adult patterns of transgene methylation are established during gametogenesis.

REFERENCES

Antequera
F.
,
Macleod
D.
,
Bird
A. P.
(
1989
)
Specific protection of methylated CpGs in mammalian nuclei.
Cell
58
,
509
517
Barlow
D. P.
,
Stoeger
,
Herrmann
B. G.
,
Saito
K.
,
Schweifer
N.
(
1991
)
The mouse insulin-like growth factor type-2 receptor is imprinted and closely linked to the Tme locus.
Nature
349
,
84
87
Bartolomei
M. S.
,
Zemel
S.
,
Tilghman
S. M.
(
1991
)
Parental imprinting of the mouse H19 gene.
Nature
351
,
153
155
Bird
A. P.
(
1986
)
CpG-rich island and the function of DNA methylation.
Nature
321
,
209
213
Bird
A. P.
(
1987
)
CpG islands as gene markers in the vertebrate nucleus.
Trends Genet
3
,
342
347
Brinster
R. L.
,
Harstad
H.
(
1977
)
Energy metabolism in primordial germ cells of the mouse.
Exp. Cell Res
109
,
111
117
Cattanach
B. M.
(
1986
)
Parental origin effects in mice.
J. Embryol. Exp. Morph
97
,
137
150
Chaillet
J. R.
,
Vogt
T. F.
,
Beier
D. R.
,
Leder
P.
(
1991
)
Parental-specific methylation of an imprinted transgene is established during gametogenesis and progressively changes during embryogenesis.
Cell
66
,
77
83
Cedar
H.
,
Razin
A.
(
1990
)
DNA methylation and development.
Biochim. Biophys. Acta
1049
,
1
8
Cox
D. R.
,
Palmiter
R. D.
(
1983
)
The metallothionein-I gene maps to mouse chromosome 8: Implications for human Menkes' disease.
Hum. Genet
64
,
61
64
Dechiara
T. M.
,
Robertson
E. J.
,
Efstratiadis
A.
(
1991
)
Parental imprinting of the mouse insulin-like growth factor II gene.
Cell
64
,
849
859
Donahue
R. P.
(
1968
)
Maturation of the mouse oocyte in vitro: I. Sequence and timing of nuclear progression.
J. Exp. Zool
169
,
237
250
Driscoll
D. J.
,
Migeon
B. R.
(
1990
)
Sex difference in methylation of single-copy genes in human meiotic germ cells: Implications for X chromosome inactivation, parental imprinting, and origin of CpG mutations.
Somat. Cell Mol. Genet
16
,
267
282
Ferguson-Smith
A. C.
,
Cattanach
B. M.
,
Barton
S. C.
,
Beechey
C. V.
,
Surani
M. A.
(
1991
)
Embryological and molecular investigations of parental imprinting on mouse chromosome 7.
Nature
351
,
667
670
Fujimoto
H.
,
Erickson
R. P.
(
1982
)
Functional assays for mRNA detect many new messages after male meiosis in mice.
Biochem. Biophys. Res. Commun
108
,
1369
1375
Glanville
N.
,
Durnam
D. M.
,
Palmiter
R. D.
(
1981
)
Structure of metallothionein-I gene and its mRNA.
Nature
292
,
267
269
Hashimoto
N.
,
Kubokawa
R.
,
Yamazaki
K.
,
Noguchi
M.
,
Kato
Y.
(
1990
)
Germ cell deficiency causes testis cord differentiation in reconstituted mouse fetal ovaries.
J. Exp. Zool
253
,
61
70
Howlett
S. K.
,
Reik
W.
(
1991
)
Methylation levels of maternal and paternal genomes during preimplantation development.
Development
113
,
119
127
Jeanpierre
M.
(
1987
)
A rapid method for the purification of DNA from blood.
Nucleic Acids. Res
15
,
9611
–.
Kolsto
A. B.
,
Kollias
G.
,
Giguere
V.
,
Isobe
K. I.
,
Prydz
H.
,
Grosveld
F.
(
1986
)
The maintenance of methylation-free islands in transgenic mice.
Nucl. Acids Res
14
,
9667
9678
Lewis
J.
,
Bird
A.
(
1991
)
DNA methylation and chromatin structure.
FEBS Lett
285
,
155
159
McLaren
A.
(
1988
)
The developmental history of female cells in mammals.
Oxford Rev. of Reprod. Biol
10
,
162
179
Migeon
B. R.
,
Holland
M. M.
,
Driscoll
D. J.
,
Robinson
J. C.
(
1991
)
Programmed demethylation in CpG islands during human fetal development.
Somat. Cell Mol. Genet
17
,
159
168
Monk
M.
,
Boubelik
M.
,
Lehnert
S.
(
1987
)
Temporal and regional changes in DNA methylation in the embryonic, extraembryonic and germ cell lineages during mouse embryo development.
Development
99
,
371
382
Monk
M.
,
Adams
R. L. P.
,
Rinaldi
A.
(
1991
)
Decrease in DNA methylase activity during preimplantation development in the mouse.
Development
112
,
189
192
Reik
W.
,
Collick
A.
,
Norris
M. L.
,
Barton
S. C.
,
Surani
M. A.
(
1987
)
Genomic imprinting determines methylation of parental alleles in transgenic mice.
Nature
328
,
248
251
Sanford
J.
,
Forrester
L.
,
Chapman
V.
(
1984
)
Methylation patterns of repetitive DNA sequences in germ cells of Mus musculus.
Nucl. Acids. Res
12
,
2823
2836
Sanford
J. P.
,
Clark
H. J.
,
Chapman
V. M.
,
Rossant
J.
(
1987
)
Differences in DNA methylation during oogenesis and spermatogenesis and their persistence during early embryogenesis in the mouse.
Genes Dev
1
,
1039
1046
Sapienza
C.
,
Peterson
A. C.
,
Rossant
J.
,
Balling
R.
(
1987
)
Degree of methylation of transgenes is dependent on gamete of origin.
Nature
328
,
251
254
Sasaki
H.
,
Hamada
T.
,
Ueda
T.
,
Seki
R.
,
Higashinakagawa
T.
,
Sakaki
Y.
(
1991
)
Inherited type of allelic methylation variations in a mouse chromosome region where an integrated transgene shows methylation imprinting.
Development
111
,
573
581
Shemer
R.
,
Walsh
A.
,
Eisenberg
S.
,
Breslow
J. L.
,
Razin
A.
(
1990
)
Tissue-specific methylation patterns and expression of the human apolipoprotein AI gene.
J. Biol. Chem
265
,
1010
1015
Shemer
R.
,
Kafri
T.
,
O'Connell
A.
,
Eisenberg
,
Breslow
J. L.
,
Razin
A.
(
1991
)
Methylation changes in the apolipoprotein AI gene during embryonic development of the mouse.
Proc. Natl. Acad. Sci. USA
88
,
11300
11304
Singer-Sam
J.
,
LeBon
J. M.
,
Tanguay
R. L.
,
Riggs
A. D.
(
1990
)
A quantitative HPaII-PCR assay to measure methylation of DNA from a small number of cells.
Nucl. Acids Res
18
,
687
–.
Solter
D.
(
1988
)
Differential imprinting and expression of maternal and paternal genomes.
Ann. Rev. Genet
22
,
127
146
Swain
J. L.
,
Stewart
T. A.
,
Leder
P.
(
1987
)
Parental legacy determines methylation and expression of an autosomal transgene: a molecular mechanism for parental imprinting.
Cell
50
,
719
727
Tazi
J.
,
Bird
A.
(
1990
)
Alternative chromatin structure at CpG islands.
Cell
60
,
909
920
Thomas
K. H.
,
Thomas
M. W.
,
Tomashefsky
P.
,
Bellve
A. R.
,
Simon
M. I.
(
1989
)
Differential gene expression during mouse spermatogenesis.
Biol. Reprod
41
,
729
739
Zimmerman
C. P.
,
Wolgemuth
D. J.
(
1984
)
Methylation of satellite sequences in mouse spermatogenic and somatic DNAs.
Nucl. Acids. Res
12
,
2807
2822
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