Human RNase III is a 160-kDa protein involved in preribosomal RNA processing

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Human RNase III is a 160 kDa protein with proline-rich, serine/arginine-rich, and RNase III domains.
• The RNase III domain specifically cleaves double-stranded RNA, not single-stranded RNA.
• The protein is ubiquitously expressed, localized to the nucleus, and its expression levels are cell cycle-independent.

Purpose of the Study:

• To investigate the function of human RNase III.
• To determine its role in pre-ribosomal RNA (pre-rRNA) processing.
• To establish the utility of antisense inhibition for analyzing novel human genes.

Main Methods:

• Expression and purification of the human RNase III domain.
• Assessment of its RNA cleavage activity.
• Antisense inhibition of RNase III expression in human cells.
• Analysis of protein localization during the cell cycle.

Main Results:

• The purified RNase III domain demonstrated specific cleavage of double-stranded RNA.
• Human RNase III translocates to the nucleolus during the S phase of the cell cycle.
• Antisense inhibition of RNase III expression led to cell death.
• This inhibition suggested a role in pre-rRNA processing, potentially at different sites than yeast RNase III.

Conclusions:

• Human RNase III plays an essential role in cell viability.
• The enzyme is involved in pre-rRNA processing.
• Antisense inhibition is an effective method for functional analysis of newly identified human genes.