Intron Retention and TE Exonization Events in ZRANB2

Area of Science:

• Evolutionary biology
• Molecular genetics
• Primate genomics

Background:

• The Zinc finger, RAN-binding domain-containing protein 2 (ZRANB2) gene plays a role in alternative splicing regulation via its arginine/serine-rich (RS) domains.
• The ZRANB2 gene contains two LINE elements (L3b, Plat_L3) located between exons 9 and 10, suggesting potential evolutionary impact.

Purpose of the Study:

• To investigate the evolutionary history and mechanisms of transposable element (TE) exonization and intron retention (IR) within the ZRANB2 gene across primate evolution.
• To identify and characterize novel ZRANB2 transcript variants arising from TE integration and alternative splicing.

Main Methods:

• Genomic PCR and RT-PCR amplification were employed to analyze ZRANB2 DNA and RNA samples from various primate species.
• Sequencing of amplified products was performed to confirm the integration and exonization of LINE elements and to characterize transcript variants.
• Differential expression analysis of ZRANB2 transcripts was conducted.

Main Results:

• Two LINE elements were found integrated in the ZRANB2 gene across all tested primate species.
• Exonization of the Plat_L3 LINE element was identified in human, rhesus monkey, crab-eating monkey, African-green monkey, and marmoset.
• Long ZRANB2 transcripts, generated through intron retention (IR), were abundantly expressed in Old World monkey lineages, indicating differential expression patterns.

Conclusions:

• The ZRANB2 gene exhibits significant evolutionary plasticity, producing at least three transcript variants through TE exonization and IR.
• ZRANB2 serves as a valuable model for studying the evolutionary dynamics of transposable elements and alternative splicing in primate genomes.
• The findings highlight the role of TEs and IR in generating transcript diversity during primate evolution.