TERribly Difficult: Searching for Telomerase RNAs in Saccharomycetes

Area of Science:

• Molecular Biology
• Genomics
• RNA Biology

Background:

• Telomerase RNA (tRNA) is essential for telomere maintenance in eukaryotes.
• Yeast tRNA sequences are large (>1000 nt) and contain functional elements.
• Detecting yeast tRNA by homology is difficult due to rapid sequence evolution, size variation, and structural plasticity, hindering genome annotation in Saccharomycotina.

Purpose of the Study:

• To address the gap in telomerase RNA annotation within Saccharomycotina genomes.
• To identify novel telomerase RNA sequences using a combination of computational methods.

Main Methods:

• Utilized a combination of diverse computational methods for sequence identification.
• Developed specific search models tailored to different phylogenetic subgroups within Saccharomycetacea.
• Focused the survey on the Saccharomycetacea subgroup due to expected sequence diversity.

Main Results:

• Successfully identified 27 new telomerase RNA sequences.
• The annotation efforts were restricted to the Saccharomycetacea subgroup.
• Even within this subgroup, phylogenetic diversity necessitated the use of distinct search models.

Conclusions:

• Closing the telomerase RNA annotation gap in Saccharomycotina is a complex task.
• Significant sequence and structural diversity of tRNA poses challenges for homology-based detection.
• Telomerase RNA remains unannotated in more distantly related Saccharomycotina branches, indicating the need for further research.