Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1995 Sep 1;310(Pt 2):637–641. doi: 10.1042/bj3100637

Secretory proteins compete for production in the mammary gland of transgenic mice.

M McClenaghan 1, A Springbett 1, R M Wallace 1, C J Wilde 1, A J Clark 1
PMCID: PMC1135943  PMID: 7654205

Abstract

To explore the possibility that genes might compete for expression, we have studied transgenic mice producing high levels of the sheep milk protein, beta-lactoglobulin (BLG), in the mammary gland. Mice carrying one or more transgene loci expressed BLG in milk at levels ranging from 7 to 33 mg/ml. The effects of BLG synthesis on the levels of endogenous milk gene expression were examined. No significant increase in total milk protein concentration was recorded even in mice expressing the largest amounts of BLG. Measurement of individual milk proteins showed that transgene protein was manufactured at the expense of host protein synthesized in the gland. Whey acidic protein production was more suppressed than casein production. Suppression of endogenous proteins was matched by a reduction in the corresponding steady-state mRNA levels; in double-transgenic mice, which expressed the largest amounts of BLG, beta-casein and whey acidic protein mRNA populations were reduced to 75 and 56% of control levels respectively. We demonstrate that an exogenous gene competes effectively for expression with endogenous genes. Possible mechanisms of competition are discussed.

Full text

PDF
637

Images in this article

639Figure 1
on p.639

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ASCHAFFENBURG R., DREWRY J. Improved method for the preparation of crystalline beta-lactoglobulin and alpha-lactalbumin from cow's milk. Biochem J. 1957 Feb;65(2):273–277. doi: 10.1042/bj0650273. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Ali S., Clark A. J. Characterization of the gene encoding ovine beta-lactoglobulin. Similarity to the genes for retinol binding protein and other secretory proteins. J Mol Biol. 1988 Feb 5;199(3):415–426. doi: 10.1016/0022-2836(88)90614-6. [DOI] [PubMed] [Google Scholar]
  3. Atwater J. A., Wisdom R., Verma I. M. Regulated mRNA stability. Annu Rev Genet. 1990;24:519–541. doi: 10.1146/annurev.ge.24.120190.002511. [DOI] [PubMed] [Google Scholar]
  4. Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
  5. Church G. M., Gilbert W. Genomic sequencing. Proc Natl Acad Sci U S A. 1984 Apr;81(7):1991–1995. doi: 10.1073/pnas.81.7.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Davis B. P., MacDonald R. J. Limited transcription of rat elastase I transgene repeats in transgenic mice. Genes Dev. 1988 Jan;2(1):13–22. doi: 10.1101/gad.2.1.13. [DOI] [PubMed] [Google Scholar]
  7. Dillon N., Grosveld F. Transcriptional regulation of multigene loci: multilevel control. Trends Genet. 1993 Apr;9(4):134–137. doi: 10.1016/0168-9525(93)90208-y. [DOI] [PubMed] [Google Scholar]
  8. Felsenfeld G. Chromatin structure and the expression of globin-encoding genes. Gene. 1993 Dec 15;135(1-2):119–124. doi: 10.1016/0378-1119(93)90056-9. [DOI] [PubMed] [Google Scholar]
  9. Flavell R. B. Inactivation of gene expression in plants as a consequence of specific sequence duplication. Proc Natl Acad Sci U S A. 1994 Apr 26;91(9):3490–3496. doi: 10.1073/pnas.91.9.3490. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Grosveld F., Antoniou M., Berry M., De Boer E., Dillon N., Ellis J., Fraser P., Hanscombe O., Hurst J., Imam A. The regulation of human globin gene switching. Philos Trans R Soc Lond B Biol Sci. 1993 Feb 27;339(1288):183–191. doi: 10.1098/rstb.1993.0015. [DOI] [PubMed] [Google Scholar]
  11. Gupta P., Rosen J. M., D'Eustachio P., Ruddle F. H. Localization of the casein gene family to a single mouse chromosome. J Cell Biol. 1982 Apr;93(1):199–204. doi: 10.1083/jcb.93.1.199. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Guyette W. A., Matusik R. J., Rosen J. M. Prolactin-mediated transcriptional and post-transcriptional control of casein gene expression. Cell. 1979 Aug;17(4):1013–1023. doi: 10.1016/0092-8674(79)90340-4. [DOI] [PubMed] [Google Scholar]
  13. Harris S., McClenaghan M., Simons J. P., Ali S., Clark A. J. Developmental regulation of the sheep beta-lactoglobulin gene in the mammary gland of transgenic mice. Dev Genet. 1991;12(4):299–307. doi: 10.1002/dvg.1020120407. [DOI] [PubMed] [Google Scholar]
  14. Mason J. O., Williams G. T., Neuberger M. S. The half-life of immunoglobulin mRNA increases during B-cell differentiation: a possible role for targeting to membrane-bound polysomes. Genes Dev. 1988 Aug;2(8):1003–1011. doi: 10.1101/gad.2.8.1003. [DOI] [PubMed] [Google Scholar]
  15. Shaw P., Sordat B., Schibler U. Developmental coordination of alpha-amylase and psp gene expression during mouse parotid gland differentiation is controlled posttranscriptionally. Cell. 1986 Oct 10;47(1):107–112. doi: 10.1016/0092-8674(86)90371-5. [DOI] [PubMed] [Google Scholar]
  16. Simons J. P., McClenaghan M., Clark A. J. Alteration of the quality of milk by expression of sheep beta-lactoglobulin in transgenic mice. Nature. 1987 Aug 6;328(6130):530–532. doi: 10.1038/328530a0. [DOI] [PubMed] [Google Scholar]
  17. Singh H., Sen R., Baltimore D., Sharp P. A. A nuclear factor that binds to a conserved sequence motif in transcriptional control elements of immunoglobulin genes. Nature. 1986 Jan 9;319(6049):154–158. doi: 10.1038/319154a0. [DOI] [PubMed] [Google Scholar]
  18. Sollner-Webb B., Reeder R. H. The nucleotide sequence of the initiation and termination sites for ribosomal RNA transcription in X. laevis. Cell. 1979 Oct;18(2):485–499. doi: 10.1016/0092-8674(79)90066-7. [DOI] [PubMed] [Google Scholar]
  19. Staudt L. M., Singh H., Sen R., Wirth T., Sharp P. A., Baltimore D. A lymphoid-specific protein binding to the octamer motif of immunoglobulin genes. Nature. 1986 Oct 16;323(6089):640–643. doi: 10.1038/323640a0. [DOI] [PubMed] [Google Scholar]
  20. Urlaub G., Mitchell P. J., Ciudad C. J., Chasin L. A. Nonsense mutations in the dihydrofolate reductase gene affect RNA processing. Mol Cell Biol. 1989 Jul;9(7):2868–2880. doi: 10.1128/mcb.9.7.2868. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Wakao H., Gouilleux F., Groner B. Mammary gland factor (MGF) is a novel member of the cytokine regulated transcription factor gene family and confers the prolactin response. EMBO J. 1994 May 1;13(9):2182–2191. doi: 10.1002/j.1460-2075.1994.tb06495.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Watson C. J., Gordon K. E., Robertson M., Clark A. J. Interaction of DNA-binding proteins with a milk protein gene promoter in vitro: identification of a mammary gland-specific factor. Nucleic Acids Res. 1991 Dec 11;19(23):6603–6610. doi: 10.1093/nar/19.23.6603. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Whitelaw C. B., Archibald A. L., Harris S., McClenaghan M., Simons J. P., Clark A. J. Targeting expression to the mammary gland: intronic sequences can enhance the efficiency of gene expression in transgenic mice. Transgenic Res. 1991 Dec;1(1):3–13. doi: 10.1007/BF02512991. [DOI] [PubMed] [Google Scholar]
  24. Whitelaw C. B., Harris S., McClenaghan M., Simons J. P., Clark A. J. Position-independent expression of the ovine beta-lactoglobulin gene in transgenic mice. Biochem J. 1992 Aug 15;286(Pt 1):31–39. doi: 10.1042/bj2860031. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Wilde C. J., Clark A. J., Kerr M. A., Knight C. H., McClenaghan M., Simons J. P. Mammary development and milk secretion in transgenic mice expressing the sheep beta-lactoglobulin gene. Biochem J. 1992 Jun 15;284(Pt 3):717–720. doi: 10.1042/bj2840717. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES