FIG. 8.

The transcriptional silencing by Kcnq1ot1 requires the linked sequences at the perinucleolar region. Production of Kcnq1ot1 on the paternal chromosome results in the recruitment of heterochromatic machinery by the Kcnq1ot1 SD. Subsequently, the heterochromatic machinery associated with the antisense RNA (shown in green squiggles) mediates the chromatin interaction in a manner analogous to that of the Xist transcript, resulting in the spreading of heterochromatic histone modifications (red blobs) in a Kcnq1ot1-dependent manner in cis. Then, the Kcnq1ot1 transcript and associated heterochromatic machinery guides the linked chromosomal domain to the perinucleolar region during mid-S phase in order to maintain bidirectional transcriptional silencing of flanking genes (red and green arrows indicate silenced and active status of a gene, respectively) through successive cell divisions.