MADS-box

The MADS box is a conserved sequence motif. The genes which contain this motif are called the MADS-box gene family.[1] The MADS box encodes the DNA-binding MADS domain. The MADS domain binds to DNA sequences of high similarity to the motif CC[A/T]6GG termed the CArG-box.[2] MADS-domain proteins are generally transcription factors.[2][3] The length of the MADS-box reported by various researchers varies somewhat, but typical lengths are in the range of 168 to 180 base pairs, i.e. the encoded MADS domain has a length of 56 to 60 amino acids.[4][5][6][7] There is evidence that the MADS domain evolved from a sequence stretch of a type II topoisomerase in a common ancestor of all extant eukaryotes.[8]

Origin of name

The first MADS-box gene to be identified was ARG80 from budding yeast, Saccharomyces cerevisiae,[9] but was at that time not recognized as a member of a large gene family. The MADS-box gene family got its name later as an acronym referring to the four founding members,[1] ignoring ARG80:

Diversity

MADS-box genes were detected in nearly all eukaryotes studied.[8] While the genomes of animals and fungi generally possess only around one to five MADS-box genes, genomes of flowering plants have around 100 MADS-box genes.[11][12] Two types of MADS-domain proteins are distinguished; the SRF-like or Type I MADS-domain proteins and the MEF2-like (after MYOCYTE-ENHANCER-FACTOR2) or Type II MADS-domain proteins.[8][13] SRF-like MADS-domain proteins in animals and fungi have a second conserved domain, the SAM (SRF, ARG80, MCM1) domain.[14] MEF2-like MADS-domain proteins in animals and fungi have the MEF2 domain as a second conserved domain.[14] In plants, the MEF2-like MADS-domain proteins are also termed MIKC-type proteins referring to their conserved domain structure, where the MADS (M) domain is followed by an Intervening (I), a Keratin-like (K) and a C-terminal domain.[11]

A geneticist intensely investigating MADS-box genes is Günter Theißen at the University of Jena. For example, he and his coworkers could show by these genes that the order of Gnetales is related more closely to the conifers than with the flowering plants.[15]

Function of MADS-box genes

MADS-box genes have a variety of functions. In animals, MADS-box genes are involved in muscle development and cell proliferation and differentiation.[14] Functions in fungi range from pheromone response to arginine metabolism.[14]

In plants, MADS-box genes are involved in controlling all major aspects of development, including male and female gametophyte development, embryo and seed development, as well as root, flower and fruit development.[11][12]

Some MADS-box genes of flowering plants have homeotic functions like the HOX genes of animals.[1] The floral homeotic MADS-box genes (such as AGAMOUS and DEFICIENS) participate in the determination of floral organ identity according to the ABC model of flower development.[16]

Another function of MADS-box genes is flowering time determination. In Arabidopsis thaliana the MADS box genes SOC1[17] and Flowering Locus C[18] (FLC) have been shown to have an important role in the integration of molecular flowering time pathways. These genes are essential for the correct timing of flowering, and help to ensure that fertilization occurs at the time of maximal reproductive potential.

References

  1. 1 2 3 Schwarz-Sommer Z, Huijser P, Nacken W, Saedler H, Sommer H: Genetic control of flower development by homeotic genes in Antirrhinum majus. Science 1990, 250:931-936
  2. 1 2 West AG, Shore P, Sharrocks AD (1 May 1997). "DNA binding by MADS-box transcription factors: a molecular mechanism for differential DNA bending". Mol. Cell. Biol. 17 (5): 2876–87. PMC 232140Freely accessible. PMID 9111360.
  3. ↑ Svensson, Mats (2000). "Evolution of a family of plant genes with regulatory functions in development; studies on Picea abies and Lycopodium annotinum" (PDF). Doctoral thesis. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Biology, Department of Evolutionary Biology. ISBN 91-554-4826-7. Retrieved 2007-07-30.
  4. ↑ Ma, K.W. et al. (2005) Myocyte enhancer factor 2 acetylation by p300 enhances its DNA binding activity, transcriptional activity, and myogenic differentiation. Mol. Cell. Biol. 25, 3575–3582
  5. ↑ Lamb, R.S. and Irish, V.F. (2003) Functional divergence within the APETALA3/PISTILLATA floral homeotic gene lineages. Proc. Natl. Acad. Sci. U.S.A. 100, 6558–6563
  6. ↑ Lu, S.H. et al. (2007) Two AGAMOUS-like MADS-box genes from Taihangia rupestris (Rosaceae) reveal independent trajectories in the evolution of class C and class D floral homeotic functions. Evol. Dev. 9, 92–104
  7. ↑ Nam, J. et al. (2003) Antiquity and evolution of the MADS-box gene family controlling flower development in plants. Mol. Biol. Evol. 20, 1435–1447
  8. 1 2 3 Gramzow L, Ritz MS, Theissen G: On the origin of MADS-domain transcription factors. Trends Genet 2010, 26:149-153.
  9. ↑ Dubois E, Bercy J, Descamps F, Messenguy F: Characterization of two new genes essential for vegetative growth in Saccharomyces cerevisiae: nucleotide sequence determination and chromosome mapping. Gene 1987, 55:265-275.
  10. ↑ Sommer H, Beltrán JP, Huijser P, Pape H, Lönnig WE, Saedler H, Schwarz-Sommer Z (1990). "Deficiens, a homeotic gene involved in the control of flower morphogenesis in Antirrhinum majus: the protein shows homology to transcription factors". EMBO J. 9 (3): 605–13. PMC 551713Freely accessible. PMID 1968830.
  11. 1 2 3 Becker A, Theissen G: The major clades of MADS-box genes and their role in the development and evolution of fl owering plants. Mol Phylogenet Evol 2003, 29:464-489.
  12. 1 2 Gramzow L, Theissen G. A hitchhiker's guide to the MADS world of plants. Genome Biol. 2010;11:214
  13. ↑ Alvarez-Buylla ER, Pelaz S, Liljegren SJ, Gold SE, Burgeff C, Ditta GS, de Pouplana LR, Martinez-Castilla L, Yanofsky MF: An ancestral MADS-box gene duplication occurred before the divergence of plants and animals. Proc Natl Acad Sci USA 2000, 97:5328-5333.
  14. 1 2 3 4 Shore P, Sharrocks AD. The MADS-box family of transcription factors. Eur J Biochem. 1995 Apr 1;229(1):1-13
  15. ↑ K.U. Winter, A. Becker, T. Münster, J.T. Kim, H. Saedler, G. Theissen G.: MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants. Proc. Natl. Acad. Sci. U.S.A. 96 (1999) 7342-7347
  16. ↑ Coen ES, Meyerowitz EM. The war of the whorls: genetic interactions controlling flower development. Nature. 1991 Sep 5;353(6339):31-7
  17. ↑ Onouchi H, Igeño MI, Périlleux C, Graves K, Coupland G (2000). "Mutagenesis of Plants Overexpressing CONSTANS Demonstrates Novel Interactions among Arabidopsis Flowering-Time Genes". Plant Cell. 12 (6): 885–900. doi:10.1105/tpc.12.6.885. PMC 149091Freely accessible. PMID 10852935.
  18. ↑ Michaels SD, Amasino RM (1999). "FLOWERING LOCUS C encodes a novel MADS domain protein that acts as a repressor of flowering". Plant Cell. 11 (5): 949–56. doi:10.1105/tpc.11.5.949. PMC 144226Freely accessible. PMID 10330478.

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