Figure 1

Characterization of OsRecQl4 and molecular analysis of knockout lines. (A) T-DNA (from POSTECH) insertion site in osrecql4-1, and Tos17 (from NIAS) insertion site in osrecql4-2. OsRecQl4 has conserved helicase domains (including DEXDc, and HELICc domain), RecQ C-terminus (RQC), and HRDC domain. Probe A (near the N-terminus, 994 bp), and probe B (part of the RQC domain, 433 bp) were used for northern blot analysis. The T-DNA line shown above the construct harbored a head-to-head insertion in exon 11. The Tos17 line carries an insertion in exon 23. (B) Northern blot analysis. OsRecQl4 mRNA is expressed strongly in the base of shoots (BS) and weakly in roots of both Dongjin and Nipponbare. mRNA was detected by both probes A and B in wild-type (WT) plants but not in osrecql4-1 or osrecql4-2. Red arrowheads indicate mRNA of OsRecQl4. The genetic background of T-DNA (osrecql4-1) is Dongjin, and that of Tos17 (osrecql4-2) is Nipponbare. 7-day-old seedlings of wild-type (segregated wild type) and mutant (homozygous). R, root; BS, base of shoot; LS, lower shoot; US, upper shoot. (C) In situ hybridization analysis. Anti-sense probes for OsRecQl4 gave strong hybridization signals around the shoot apical meristem (SAM) and the root apical merstem (RAM). OsRecQl4 is expressed mainly in the meristem. (D) Sequence of the osrecql4-1 and osrecql4-2 insertion site. osrecql4-1 has a genomic deletion of 65 bp in the insertion region, exon 11. osrecql4-2 has a genomic overlap of 5 bp in the insertion region, exon 23.