Comparison of mammary gland involution between 129S1 and C57BL/6 inbred mouse strains: differential regulation of Bcl2a1, Trp53, Cebpb, and Cebpd expression.
Genetic engineering has made the mouse an invaluable tool to address the function of individual genes in a targeted manner. Over the last decade it has become apparent that the genetic mouse strain background can significantly influence the phenotype of an engineered mouse. Therefore, it is essential to characterize the biology of the different wild-type background strains. In this study, we have compared mouse mammary gland involution in the 129S1 and C57BL/6 inbred strains and report significant differences at the molecular level with differential expression of Bcl2a1 (Bfl1), Trp53 (p53), Cebpb (C/EBP beta), and Cebpd (C/EBP delta). The C57BL/6 strain exhibits dynamic responses with induction of Trp53 and Cebpd and concomitant downregulation of Bcl2a1 during the first phase of involution. In contrast, expression of these genes does not change significantly in 129S1 mice. During the second phase, C57BL/6 glands contain more Cebpb than 129S1 glands. Nevertheless, involution proceeds morphologically with similar kinetics in both strains. The data demonstrate that the genetic response of mammary tissue varies significantly between 129S1 and C57BL/6. These results may provide a basis for the interpretation of strain-specific phenotypes in engineered mice and underline the importance of pure strains for large-scale expression studies with mutant mice.
Regulation of Cell Growth Laboratory, Center for Cancer Research, National Cancer Institute, Natinal Institutes of Health, PO Box B, Frederick, MD 21702, USA.
Muthusamy
M
Thangaraju
Shikha
S
Sharan
Esta
E
Sterneck
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D005260:Female; D005786:Gene Expression Regulation; D007700:Kinetics; D007774:Lactation / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D015778:Minor Histocompatibility Antigens; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D013997:Time Factors; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
C096816:BCL2-related protein A1; D022762:CCAAT-Enhancer-Binding Proteins; C497250:Ddit3 protein, mouse; D015778:Minor Histocompatibility Antigens; D019253:Proto-Oncogene Proteins c-bcl-2; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D051742:Transcription Factor CHOP