title: A model for Arabidopsis class-1 KNOX gene function.
abstract: The Arabidopsis class-1 KNOX genes STM, BP/KNAT1, KNAT2 and KNAT6 encode homeodomain transcriptional regulators important for shoot apical meristem (SAM) and carpel development. During vegetative growth, STM is required to establish and maintain the stem cell pool of the SAM, a function replaceable by ectopic expression of BP/KNAT1 but not of other class-1 KNOX genes. We recently demonstrated additional STM roles in the development of the central floral whorl and subsequent formation of carpels, a function replaceable by ectopic KNAT2 expression. However, STM is normally required for BP/KNAT1 and KNAT2 expression, explaining why it is essential for both SAM and carpel development. We propose therefore that STM provides the critical KNOX function in these processes and that the SAM- and carpel-promoting activities of STM are redundantly duplicated in BP/KNAT1 and KNAT2 respectively. Here we show that ectopic KNAT2 expression can restore carpel development to stm mutants, but fails to restore proper development of the central floral whorl, which requires a function analogous to the SAM-promoting activities of STM and BP/KNAT1. Similarly, we show that ectopic KNAT2 expression does not restore normal meristem organisation to the SAM. We propose a model for discrete and overlapping class-1 KNOX gene function in Arabidopsis.
authors.affiliation: Institute of Biotechnology; University of Cambridge; Cambridge UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Scofield
authors.forename: Walter
authors.initials: W
authors.lastname: Dewitte
authors.forename: James Ah
authors.initials: JA
authors.lastname: Murray
references.citation: Plant Mol Biol. 2006 Apr;60(6):929-46
references.pmid: 16724262
references.citation: Plant J. 2007 Jun;50(5):767-81
references.pmid: 17461793
references.citation: Cell. 2001 Jun 15;105(6):793-803
references.pmid: 11440721
references.citation: Development. 2002 Jul;129(13):3195-206
references.pmid: 12070094
references.citation: Nature. 1996 Jan 4;379(6560):66-9
references.pmid: 8538741
references.citation: Science. 2000 Jul 28;289(5479):617-9
references.pmid: 10915624
references.citation: Proc Natl Acad Sci U S A. 2002 Apr 2;99(7):4730-5
references.pmid: 11917137
references.citation: Cell. 2001 Jun 15;105(6):805-14
references.pmid: 11440722
references.citation: Plant Physiol. 2002 Jun;129(2):565-75
references.pmid: 12068101
references.citation: Development. 1996 May;122(5):1567-75
references.pmid: 8625843
references.citation: Development. 2002 Apr;129(8):1957-65
references.pmid: 11934861
references.citation: Plant Cell. 1996 Aug;8(8):1277-89
references.pmid: 8776897
references.citation: Plant Cell. 1994 Dec;6(12):1859-76
references.pmid: 7866029
references.citation: Plant Cell. 2006 Aug;18(8):1900-7
references.pmid: 16798887
references.citation: Plant Mol Biol. 2004 Jan;54(1):71-84
references.pmid: 15159635
references.citation: Nature. 2000 Dec 21-28;408(6815):967-71
references.pmid: 11140682
references.citation: Plant Cell. 2002 Mar;14(3):547-58
references.pmid: 11910003
references.citation: Cell. 2000 Mar 17;100(6):635-44
references.pmid: 10761929
references.citation: Plant Cell. 2001 Aug;13(8):1719-34
references.pmid: 11487688
references.citation: Dev Biol. 2000 Feb 15;218(2):341-53
references.pmid: 10656774
references.citation: Plant J. 1996 Dec;10(6):967-79
references.pmid: 9011081