Comparative methylation analysis of murine transgenes that undergo or escape X-chromosome inactivation.
We analyzed an X-linked metallothionein-vasopressin (MTVP) fusion transgene that undergoes X-chromosome inactivation (X inactivation) and an X-linked transferrin (TFN) transgene that escapes X inactivation with respect to methylation in the 5' regulatory regions. The MTVP transgene promoter region is unmethylated when the transgene is on the active X chromosome and methylated when on the inactive X chromosome. Interestingly, the MTVP transgene is not detectably transcribed from the male X chromosome, although it is unmethylated, consistent with its availability for transcription. The TFN transgene promoter region is hypomethylated on both the active and inactive X chromosomes, consistent with its expression from both chromosomes. The TFN and MTVP transgenes have been mapped to chromosomal regions D and C, respectively, by fluorescence in situ hybridization. These observations are discussed in the context of our understanding of the role of DNA methylation in the spread and maintenance of X-chromosome inactivation.
Goldman
M A
MA
Department of Biology, San Francisco State University, CA 94132-1722, USA. goldman@sfsu.edu
Reeves
P S
PS
Wirth
C M
CM
Zupko
W J
WJ
Wong
M A
MA
Edelhoff
S
S
Disteche
C M
CM
D000818:Animals; D019677:Artificial Gene Fusion; D015152:Blotting, Northern; D002874:Chromosome Mapping; D019175:DNA Methylation; D015342:DNA Probes; D004303:Dosage Compensation, Genetic; D005260:Female; D018392:Genomic Imprinting; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D011401:Promoter Regions, Genetic; D014168:Transferrin / Q000235:genetics / Q000378:metabolism; D019076:Transgenes / Q000235:genetics*; D014667:Vasopressins / Q000235:genetics / Q000378:metabolism
D015342:DNA Probes; D014168:Transferrin; D014667:Vasopressins; D008668:Metallothionein