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 and history of research

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:

• MCM1 from the budding yeast, Saccharomyces cerevisiae,
• AGAMOUS from the thale cress Arabidopsis thaliana,
• DEFICIENS from the snapdragon Antirrhinum majus,^[10]
• SRF from the human Homo sapiens.

In A. thaliana, A. majus, and Zea mays this motif is involved in floral development. Early study in these model angiosperms was the beginning of research into the molecular evolution of floral structure in general, as well as their role in nonflowering plants.^[11]

Diversity

MADS-box genes have been 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.^[12][13] 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.^[12] In plants, MADS-domain protein form tetramers and this is thought to be central for their function.^[15][16] The structure of the tetramerisation domain of the MADS-domain protein SEPALLATA3 was solved illustrating the structural basis for tetramer formation^[17]

A geneticist intensely investigating MADS-box genes is Günter Theißen at the University of Jena. For example, he and his coworkers have used these genes to show that the order Gnetales is more closely related to the conifers than to the flowering plants.^[18]

MADS-box is under-studied in wheat as of 2021^[update].^[19]

In Zea mays the mutant Tunicate1 produces pod corn. Tunicate1 is a mutant of Z. mays MADS19 (ZMM19), in the SHORT VEGETATIVE PHASE gene family. ZMM19 can be ectopically expressed.^[19]

Such ectopic expression of ZMM19 in A. thaliana enlarges sepals, suggesting conservation.^[19]

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.^[12][13]

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.^[20]

Another function of MADS-box genes is flowering time determination. In Arabidopsis thaliana the MADS box genes SOC1^[21] and Flowering Locus C^[22] (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.

Structure of MADS-box proteins

The MADS box protein structure is characterized by four domains. At the N terminal end is the highly conserved MADS DNA binding domain.^[23] Next to the MADS domain is the moderately conserved Intervening (I) and Keratin-like (K) domains, which are involved in specific protein-protein interactions.^[23] The carboxyl terminal (C) domain is highly variable and is involved in transcriptional activation and assemblage of heterodimers and multimeric protein complexes.^[24]

References

1. Schwarz-Sommer Z, Huijser P, Nacken W, Saedler H, Sommer H (November 1990). "Genetic Control of Flower Development by Homeotic Genes in Antirrhinum majus". Science. 250 (4983): 931–6. Bibcode:1990Sci...250..931S. doi:10.1126/science.250.4983.931. PMID 17746916. S2CID 15848590.
2. West AG, Shore P, Sharrocks AD (May 1997). "DNA binding by MADS-box transcription factors: a molecular mechanism for differential DNA bending". Molecular and Cellular Biology. 17 (5): 2876–87. doi:10.1128/MCB.17.5.2876. PMC 232140. PMID 9111360.
3. Svensson M (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 978-91-554-4826-4. Retrieved 2007-07-30.
4. Ma K, Chan JK, Zhu G, Wu Z (May 2005). "Myocyte enhancer factor 2 acetylation by p300 enhances its DNA binding activity, transcriptional activity, and myogenic differentiation". Molecular and Cellular Biology. 25 (9): 3575–82. doi:10.1128/MCB.25.9.3575-3582.2005. PMC 1084296. PMID 15831463.
5. Lamb RS, Irish VF (May 2003). "Functional divergence within the APETALA3/PISTILLATA floral homeotic gene lineages". Proceedings of the National Academy of Sciences of the United States of America. 100 (11): 6558–63. Bibcode:2003PNAS..100.6558L. doi:10.1073/pnas.0631708100. PMC 164485. PMID 12746493.
6. Nam J, dePamphilis CW, Ma H, Nei M (September 2003). "Antiquity and evolution of the MADS-box gene family controlling flower development in plants". Molecular Biology and Evolution. 20 (9): 1435–47. doi:10.1093/molbev/msg152. PMID 12777513.
7. Lü S, Du X, Lu W, Chong K, Meng Z (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". Evolution & Development. 9 (1): 92–104. doi:10.1111/j.1525-142X.2006.00140.x. PMID 17227369. S2CID 9253584.
8. Gramzow L, Ritz MS, Theissen G (April 2010). "On the origin of MADS-domain transcription factors". Trends in Genetics. 26 (4): 149–53. doi:10.1016/j.tig.2010.01.004. PMID 20219261.
9. Dubois E, Bercy J, Descamps F, Messenguy F (1987). "Characterization of two new genes essential for vegetative growth in Saccharomyces cerevisiae: nucleotide sequence determination and chromosome mapping". Gene. 55 (2–3): 265–275. doi:10.1016/0378-1119(87)90286-1. PMID 3311883.
10. Sommer H, Beltrán JP, Huijser P, Pape H, Lönnig WE, Saedler H, Schwarz-Sommer Z (March 1990). "Deficiens, a homeotic gene involved in the control of flower morphogenesis in Antirrhinum majus: the protein shows homology to transcription factors". The EMBO Journal. 9 (3): 605–13. doi:10.1002/j.1460-2075.1990.tb08152.x. PMC 551713. PMID 1968830.
11. Friedman, William E.; Moore, Richard C.; Purugganan, Michael D. (2004). "The evolution of plant development". American Journal of Botany. 91 (10). Botanical Society of America (Wiley): 1726–1741. doi:10.3732/ajb.91.10.1726. ISSN 0002-9122. PMID 21652320.
12. Becker A, Theissen G (December 2003). "The major clades of MADS-box genes and their role in the development and evolution of flowering plants". Molecular Phylogenetics and Evolution. 29 (3): 464–89. doi:10.1016/S1055-7903(03)00207-0. PMID 14615187.
13. Gramzow L, Theissen G (2010). "A hitchhiker's guide to the MADS world of plants". Genome Biology. 11 (6): 214. doi:10.1186/gb-2010-11-6-214. PMC 2911102. PMID 20587009.
14. Shore P, Sharrocks AD (April 1995). "The MADS-box family of transcription factors". European Journal of Biochemistry. 229 (1): 1–13. doi:10.1111/j.1432-1033.1995.0001l.x. PMID 7744019.
15. Theissen G, Saedler H (January 2001). "Plant biology. Floral quartets". Nature. 409 (6819): 469–71. Bibcode:2001Natur.409..469T. doi:10.1038/35054172. PMID 11206529. S2CID 5325496.
16. Smaczniak C, Immink RG, Muiño JM, Blanvillain R, Busscher M, Busscher-Lange J, Dinh QD, Liu S, Westphal AH, Boeren S, Parcy F, Xu L, Carles CC, Angenent GC, Kaufmann K (January 2012). "Characterization of MADS-domain transcription factor complexes in Arabidopsis flower development". Proceedings of the National Academy of Sciences of the United States of America. 109 (5): 1560–5. Bibcode:2012PNAS..109.1560S. doi:10.1073/pnas.1112871109. PMC 3277181. PMID 22238427.
17. Puranik S, Acajjaoui S, Conn S, Costa L, Conn V, Vial A, Marcellin R, Melzer R, Brown E, Hart D, Theißen G, Silva CS, Parcy F, Dumas R, Nanao M, Zubieta C (September 2014). "Structural basis for the oligomerization of the MADS domain transcription factor SEPALLATA3 in Arabidopsis". The Plant Cell. 26 (9): 3603–15. doi:10.1105/tpc.114.127910. PMC 4213154. PMID 25228343.
18. Winter KU, Becker A, Münster T, Kim JT, Saedler H, Theissen G (June 1999). "MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants". Proceedings of the National Academy of Sciences of the United States of America. 96 (13): 7342–7. Bibcode:1999PNAS...96.7342W. doi:10.1073/pnas.96.13.7342. PMC 22087. PMID 10377416.
19. Adamski, Nikolai M; Simmonds, James (ORCID); Brinton, Jemima F (ORCID); Backhaus, Anna E (ORCID); Chen, Yi (ORCID); Smedley, Mark (ORCID); Hayta, Sadiye (ORCID); Florio, Tobin (ORCID); Crane, Pamela (ORCID); Scott, Peter (ORCID); Pieri, Alice (ORCID); Hall, Olyvia (ORCID); Barclay, J Elaine; Clayton, Myles (ORCID); Doonan, John H (ORCID); Nibau, Candida (ORCID); Uauy, Cristobal (ORCID) (2021-05-01). "Ectopic expression of Triticum polonicum VRT-A2 underlies elongated glumes and grains in hexaploid wheat in a dosage-dependent manner". The Plant Cell. 33 (7). American Society of Plant Biologists (OUP): 2296–2319. doi:10.1093/plcell/koab119. ISSN 1532-298X. PMC 8364232. PMID 34009390. {{cite journal}}: External link in |first10=, |first11=, |first12=, |first14=, |first15=, |first16=, |first17=, |first2=, |first3=, |first4=, |first5=, |first6=, |first7=, |first8=, and |first9= (help)
20. Coen ES, Meyerowitz EM (September 1991). "The war of the whorls: genetic interactions controlling flower development". Nature. 353 (6339): 31–7. Bibcode:1991Natur.353...31C. doi:10.1038/353031a0. PMID 1715520. S2CID 4276098.
21. Onouchi H, Igeño MI, Périlleux C, Graves K, Coupland G (June 2000). "Mutagenesis of plants overexpressing CONSTANS demonstrates novel interactions among Arabidopsis flowering-time genes". The Plant Cell. 12 (6): 885–900. doi:10.1105/tpc.12.6.885. PMC 149091. PMID 10852935.
22. Michaels SD, Amasino RM (May 1999). "FLOWERING LOCUS C encodes a novel MADS domain protein that acts as a repressor of flowering". The Plant Cell. 11 (5): 949–56. doi:10.1105/tpc.11.5.949. PMC 144226. PMID 10330478.
23. Jack, Thomas (2004). "Molecular and genetic mechanisms of floral control". The Plant Cell. 16 Suppl (Suppl): S1 – S17. doi:10.1105/tpc.017038. ISSN 1040-4651. PMC 2643400. PMID 15020744.
24. Riechmann, Jose Luis; Meyerowitz, Elliot M. (1997). "MADS Domain Proteins in Plant Development". Biological Chemistry. 378 (10): 1079–1101. ISSN 1431-6730. PMID 9372178.

External links

• M type MADS family at PlantTFDB: Plant Transcription Factor Database
• MIKC type MADS family at PlantTFDB: Plant Transcription Factor Database