Centromeric Transcription Regulates Aurora-B Localization and Activation.

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Centromeric transcription is conserved across species.
• The precise role of centromeric transcription during mitosis remains largely unknown.
• Long noncoding RNAs (lncRNAs) are increasingly recognized for their regulatory functions.

Purpose of the Study:

• To investigate the function of centromeric transcription during mitosis.
• To identify the products of centromeric transcription and their cellular localization.
• To determine the molecular mechanisms by which centromeric transcripts influence mitotic processes.

Main Methods:

• Xenopus egg extracts were used to study centromeric transcription.
• Centromeric RNA (cen-RNA) was identified and its localization analyzed.
• In vitro and in vivo binding assays were performed to assess cen-RNA interactions with the chromosomal passenger complex (CPC).
• Transcriptional inhibition and antisense inhibition were employed to study cen-RNA function.
• Immunofluorescence microscopy was used to examine CPC localization and Aurora-B activation.
• Kinetochore-microtubule attachment was assessed.

Main Results:

• Centromeres in Xenopus egg extracts are transcribed into a long noncoding RNA (lncRNA), termed cen-RNA.
• cen-RNA localizes to mitotic centromeres, chromatin, and spindles.
• cen-RNAs bind to the chromosomal passenger complex (CPC) both in vitro and in vivo.
• Inhibition of cen-RNA transcription or levels disrupts CPC localization to the inner centromere.
• cen-RNA is required for proper activation of the CPC component Aurora-B, independent of known recruitment pathways.
• Transcription is essential for the normal bipolar attachment of kinetochores to the mitotic spindle.
• cen-RNA plays a role in regulating CPC localization and activation.

Conclusions:

• Centromeric transcription generates lncRNAs (cen-RNAs) that are integral components of the centromere during mitosis.
• cen-RNAs regulate the localization and activation of the chromosomal passenger complex (CPC).
• This regulation by cen-RNAs is critical for proper kinetochore function and bipolar spindle attachment.
• The study demonstrates a novel mechanism by which lncRNAs contribute to accurate chromosome segregation.