plex9.2

ID

ZDB-GENE-110411-9

Name

PML-like exon 9.2

Symbol

plex9.2 Nomenclature History

Previous Names

• trex4 (1)
• si:ch1073-296i8.2 (2)

Type

protein_coding_gene

Location

Chr: 25 Mapping Details/Browsers

Description

Predicted to have 3'-5'-exodeoxyribonuclease activity. Human ortholog(s) of this gene implicated in Aicardi-Goutieres syndrome; Chilblain lupus; retinal vasculopathy with cerebral leukodystrophy; and systemic lupus erythematosus. Orthologous to human TREX1 (three prime repair exonuclease 1) and TREX2 (three prime repair exonuclease 2).

Genome Resources

• Alliance (1)
• Gene:100005742 (1)
• VEGA:OTTDARG00000035592 (1)
• Ensembl(GRCz11):ENSDARG00000093773 (1)

Note

(from Mathavarajah, et al., pre-print, 2022) plex9.2 gene was misannotated as trex4 (renamed in 2020), due to homology to trex1; however, phylogenetic analysis, backed up by synteny analysis between the spotted gar genome and the zebrafish genome, supports a different evolutionary origin completely. This gene, PML-like exon 9.2 (plex9.2), is one of two genes in the same chromosomal locus (NOT a result of whole genome duplication) that shares very high homology with the spotted gar (Lepisosteus oculatus) PML. It resides in a chromosomal region with high synteny between gar and zebrafish, which also supports this gene being directly related to plex9 genes adjacent to the PML gene in the spotted gar genome on the same chromosomal region. These exonuclease genes are likely derived from the C-terminal exonuclease domain encoded by the PML vertebrate progenitor gene that was consequently lost in zebrafish and is highly similar to exon 9 of human PML, which encodes a now inactive exonuclease domain that nonetheless can restrict LINE-1 retrotransposons. The plex9.2 (and related plex9.1) gene is an example of convergent evolution with trex1 (both plex9.2 and trex1 can restrict LINE-1 retrotransposons in our study) but is most definitely not a trex-related gene.

Comparative Information