Fig. 4. erl1-2 and erl2-1 are null alleles. (A,B) Structure of ERL1 (A) and ERL2 (B) genes and T-DNA insertion sites. The insertion in erl2-1 consists of two T-DNAs with inverse orientation. The sequence of ERL1 and ERL2 adjacent to the insertion is shown in upper case. The T-DNA sequence is in lower case. (C-E) Semi-quantitative RT-PCR analysis of ERECTA, ERL1 and ERL2 transcripts in erl1-2 (C), erl2-1 (D) and erecta-105 (E) mutant backgrounds. erl1-2, erl2-1 and erecta-105 plants do not have detectable levels of ERL1, ERL2 and ERECTA mRNA, respectively. None of these null mutations affect expression levels of other members of ERECTA-family. The actin fragment was amplified simultaneously as a control. ERECTA, ERL1 and ERL2 were amplified for 35 (C,D) or 32 (E) cycles; the control actin was amplified for 30 cycles.