Figure 2.

Structure of Rice Centromeric BAC 17p22.

(A) The middle diagram shows that the insert of BAC 17p22 contains two blocks of the CentO satellite that are 9 and 39.5 kb, respectively, and that are separated by two CRR-related DNA sequences. The top diagram shows the structure of the two CRR-related fragments. The 9.2-kb fragment contains three truncated or rearranged CRR elements. The 4.4-kb fragment contains a single CRR element with two LTRs. Each CRR element is represented by a purple arrow. Open arrows indicate open reading frames; light blue arrows indicate LTRs; the dark blue arrow indicates the reverse transcriptase domain; red arrows indicate the integrase domain; the green arrow indicates the protease domain; yellow arrows indicate the gag domain. The bottom diagram shows that the two CRR-related DNA fragments are covered by six plasmid clones: pRCE1, pRCE2, pRCH1, pRCH2, pRCH3, and pRCS1. These six plasmid clones were used as the CRR probe for FISH analysis.

(B) A fiber-FISH image of a single 17p22 molecule visualized by three probes: BAC vector (blue), CRR probe (red), and CentO probe pRCS2 (green). The sequence assembly of BAC 17p22 in (A) is confirmed by the fiber-FISH result.