CXorf65 (chromosome X open reading frame 65) is a protein‑coding gene located on the minus strand of human chromosome X at band Xq13.1. The gene spans approximately 2.85 kb and consists of six exons that produce an 834‑nucleotide mRNA transcript. Translation of the primary transcript yields an uncharacterized protein of 183 amino acids (≈21.3 kDa).
Gene and Protein Characteristics
- Official Symbol: CXorf65
- Synonyms: LOC158830, A6NEN9
- Entrez Gene ID: 158830
- Ensembl ID: ENSG00000204165
- UniProt Accession: A6NEN9 (human), Q3V2K1 (mouse ortholog)
- Protein Family: Pfam 15874, a two‑member family associated with conserved putative interleukin‑2‑receptor‑gamma (IL2RG)–like domains.
Isoforms
CXorf65 is reported to have three isoforms:
- Uncharacterized protein CXorf65 – the canonical 183‑aa protein.
- CXorf65 isoform X1 – generated by alternative splicing that skips exon 4, resulting in a shorter 160‑aa product.
- Non‑coding RNA sequence – a transcript containing a frameshift‑inducing 19‑bp deletion in exon 2, leading to a premature stop codon and no functional protein.
Only the canonical isoform is known to produce a stable protein; the functional relevance of the other isoforms remains unclear.
Expression Profile
RNA‑seq data indicate that CXorf65 is ubiquitously expressed at low levels (typically 1–7 RPKM) across most human tissues, with relatively higher expression observed in testis.
Evolutionary Conservation
Orthologs of CXorf65 are present in mammals, including a mouse counterpart (gene ID 245536, Ensembl ENSMUSG00000090141) that maps to the X chromosome. The gene belongs to a conserved family of proteins with putative IL2RG‑like domains, suggesting a possible, yet uncharacterized, role in immune‑related or reproductive processes.
Genomic Context
CXorf65 resides within gene cluster 31, a group of 413 genes implicated in spermatid development and spermatogenesis. Its genomic neighborhood includes several neighboring genes on the X chromosome, as illustrated in locus schematics available from genome browsers.
Functional Insights
To date, CXorf65 is classified as an uncharacterized protein; no definitive biological function, disease association, or protein‑protein interaction network has been firmly established. Ongoing research may clarify its role, particularly given its conserved domain architecture and testis‑biased expression pattern.