Fig. 2. Weak alleles of gnom have a number of post-embryonic growth phenotypes. (A) Diagram of GNOM protein depicting the N-terminal dimerisation and cyclophilin-binding (DCB) domain (Grebe et al., 2000) and the central, catalytic Sec7 domain (Shevell et al., 1994). Small arrowheads indicate positions of premature stop codons leading to strong gnom phenotypes, grey/black double-arrowhead indicates splice-site mutation in gnom^S28 (grey), leading to an out-of-frame stop (black). Arrows indicate positions of the two complementing missense mutations (Busch et al., 1996). Large arrowheads indicate mutations leading to premature stops in the weak alleles. gnom^SIT4 is a CAA to TAA nonsense mutation of codon 984. Grey/black double arrowhead indicates the AGC to AC frame-shift mutation of codon 1369 leading to an out-of-frame stop (black) in gnom^R5. (B) Immunoblot of strong and weak gnom alleles. gnom^B4049/emb30-1 (gnom^B/E), full-length mutant protein (165 kDa, black arrowhead); gnom^S28, negative control. White arrowheads indicate the expected positions of the truncated proteins of gnom^R5 (155 kDa) and gnom^SIT4 (110 kDa). Four-times as much protein was loaded on the rightmost lane as on the lane to its left. (C) Overview of phenotypic series of 8-day-old seedlings from a strong (emb30-1), a weak (gnom^R5) and a very weak gnom line (gnom^B/E). (D-G) Cotyledon vasculature of (D) strong, (E) weak, (F) very weak gnom. (G) Vasculature of wild type. (H-K) Rosette stage plants: (H) gnom^R5; (I) size comparison between wild-type sister and gnom^R5; arrowheads indicate extremely dwarfed gnom^R5 plantlets; (J) gnom^B/E; (K) wild type. (L-M) Flowering shoots of (L) 7-week and (M) 11-week-old plants of Col and gnom^B/E. (N) Plastochrons of Col and gnom^B/E. n=31 and n=43 per time-point for Col and gnom^B/E, respectively. (O) Comparative histogram between Col and gnom^B/E, showing percentages of plants bolting per indicated time period. n=19 and n=18 for Col and gnom^B/E, respectively. There was a significant difference between the genotypes (P<0.001). (P) Primary inflorescence height of Col and gnom^B/E at maturity. There was a significant difference between the genotypes (P<0.001). (Q) Histogram of percentage of plants with a given number of rosette side branches at several time points. n=47 and n=37 for Col and gnom^B/E, respectively. At day 80, there was a significant difference between the genotypes (P<0.001).