Specific features of telomerase RNA from Hansenula polymorpha

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Telomeres protect eukaryotic chromosomes, and their length is maintained by telomerase.
• Telomerase is a ribonucleoprotein enzyme composed of TERT protein and a variable RNA subunit (TER).
• Understanding telomerase RNA structure and function is crucial for genome stability research.

Purpose of the Study:

• To identify and characterize the telomerase RNA (HpTER) from the thermotolerant yeast Hansenula polymorpha.
• To investigate the functional role of HpTER in telomere maintenance and length regulation.
• To elucidate the structural features of HpTER and their impact on telomerase activity.

Main Methods:

• Identification and sequencing of HpTER from Hansenula polymorpha.
• In vitro telomerase assays to study reverse transcription and nucleotide addition.
• Chromosomal end sequencing to analyze telomere structure.
• Mutational analysis of HpTER to assess its role in telomere length regulation.

Main Results:

• The telomerase RNA from Hansenula polymorpha (HpTER) was identified and its structural features described.
• H. polymorpha telomerase was shown to extend beyond the predicted template boundary, adding a non-telomeric dT.
• This terminal dT was specifically found at the 3' end of H. polymorpha telomeres.
• Mutational analysis confirmed that dT incorporation by HpTER limits telomere length.

Conclusions:

• The study identified HpTER and elucidated its unique role in telomere maintenance.
• HpTER's ability to add a terminal dT is a novel mechanism for limiting telomere length.
• This finding contributes to understanding the diversity of telomerase function across eukaryotes and genome integrity.