MADS-box proteins contain a highly conserved DNA -binding domain at
the N-terminus and function as transcription factors to regulate
diverse processes, such as growth and development among others. The
transcription factor can act as a homodimer or a heterodimer.
The zmm28 gene encodes a MIKC-type MADS-box
transcriptional factor where the MADS (M) domain is followed by
Intervening (I), Keratin-like (K), and C-terminal domains and
belongs to the AP1-FUl clade of MADS-box genes. Constitutive
expression of zmm28 resulted in greater height, increased
yield, increased photosynthesis in leaves (higher expression of C4
photosynthetic genes), increased nitrogen assimilation (through
improved nitrogenase reductase activity) and modulation of
phytohormone (gibberellin and auxin) signalling.