Identification and characterization of sea squirt telomerase reverse transcriptase.

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Genetics

Background:

• Telomerase is crucial for maintaining telomere length and chromosome stability in eukaryotes.
• The telomerase complex comprises the catalytic telomerase reverse transcriptase protein (TERT) and telomerase RNA.
• Sea squirts (urochordates) are evolutionarily significant, offering insights into vertebrate gene origins.

Purpose of the Study:

• To clone and characterize the TERT genes from two sea squirt species, Ciona intestinalis and Ciona savignyi.
• To compare these TERT genes with their vertebrate counterparts.
• To investigate the evolutionary conservation of TERT structure and identify novel motifs.

Main Methods:

• Gene cloning and sequencing of TERT from Ciona intestinalis and Ciona savignyi.
• Bioinformatic analysis of TERT gene structure, including exon-intron organization.
• Sequence alignment of Ciona TERT with vertebrate TERT sequences to identify conserved motifs.
• Gene expression analysis using tissue samples.

Main Results:

• The TERT gene from Ciona intestinalis (CinTERT) has 17 exons, similar to vertebrate TERT genes.
• The TERT gene from Ciona savignyi (CsaTERT) surprisingly lacks introns.
• Both Ciona TERTs possess all known reverse transcriptase (RT) motifs, and a novel motif (motif 3) was identified between motifs 2 and A.
• Ciona TERT gene expression was detected in most tissues, excluding the brain and heart.

Conclusions:

• This study reports the TERT gene in invertebrate chordates for the first time.
• The findings highlight the structural similarities and differences in TERT genes between sea squirts and vertebrates.
• The discovery of motif 3 suggests a previously unrecognized conserved feature in TERT evolution.