Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand.
Plant J. 2010 Apr;62(2):203-14. doi: 10.1111/j.1365-313X.2010.04139.x. Epub 2010 Jan 18.
The MADS-box family of transcription factors have diverse developmental roles in flower pattern formation, gametophyte cell division and fruit differentiation. The B-sister MADS-box proteins are most similar to the B-class floral homeotic proteins, and are expressed in female reproductive organs. The Arabidopsis B-sister MADS-box protein, TT16, is necessary for inner integument differentiation. We have functionally characterized the only other B-sister MADS-box gene in Arabidopsis, AGL63, renamed here as GORDITA (GOA). A loss-of-function mutation in goa or reduction of endogenous GOA expression results in larger fruits, illustrating its novel function in regulating fruit growth. Consistent with its function, GOA expression is detected in the walls of the valves and throughout the replum of the fruit. Our phenotypic and molecular analyses of 35S::GOA and goa plants show that GOA controls organ size via cell expansion. Further, functional studies of goa tt16 double mutants have shown their additive role in controlling seed coat development, and have revealed the importance of GOA expression in the outer integument. Together, our studies provide evidence of a new regulatory role for a B-sister MADS-box gene in the control of organ growth.
MADS 盒家族转录因子在花模式形成、配子体细胞分裂和果实分化中具有多种发育作用。B 类姐妹 MADS 盒蛋白与 B 类花同源蛋白最相似，并在雌性生殖器官中表达。拟南芥 B 类姐妹 MADS 盒蛋白 TT16 对于内种皮的分化是必需的。我们对拟南芥中唯一的另一个 B 类姐妹 MADS 盒基因 AGL63 进行了功能表征，在这里将其重新命名为 GORDITA（GOA）。goa 或内源 GOA 表达减少的功能丧失突变导致果实更大，这说明了它在调节果实生长中的新功能。与它的功能一致，GOA 的表达在果实的瓣膜壁和胎座中都有检测到。我们对 35S::GOA 和 goa 植株的表型和分子分析表明，GOA 通过细胞扩张来控制器官大小。此外，goa tt16 双突变体的功能研究表明，它们在控制种皮发育方面具有累加作用，并揭示了 GOA 表达在外种皮中的重要性。总之，我们的研究为 B 类姐妹 MADS 盒基因在控制器官生长中的新调节作用提供了证据。
