Involved in mRNA export and mRNA coupled transcription activation (PubMed:18034162, PubMed:27016737, PubMed:33602059). Component of the nuclear pore complex (NPC)-associated TREX-2/AMEX complex (anchoring and mRNA export complex) which functions in docking export-competent ribonucleoprotein particles (mRNPs) to the nuclear entrance of the nuclear pore complex (nuclear basket), thereby enabling the export of mRNAs to the cytoplasm through the nuclear pores (PubMed:18034162, PubMed:27016737). The TREX-2/AMEX complex also functions with the transcriptional coactivator SAGA/TFTC complex, to anchor a subset of transcription sites to the nuclear pore complex basket in order to achieve efficient transcription and export of their resulting mRNAs (PubMed:18034162). Within the complex, required for localization of e(y)2 to the nuclear periphery (PubMed:18034162). Component of the nuclear pore complex (NPC)-associated TREX-2/AMEX complex (anchoring and mRNA export complex), composed of e(y)2, xmas and PCID2 (PubMed:18034162, PubMed:27016737). Within the TREX-2/ AMEX complex, interactions with e(y)2 is required for localization of e(y)2 to the nuclear periphery (PubMed:18034162, Ref.7). Interaction between the TREX-2/AMEX complex and the ORC complex is required for ORC localization to mRNPs, and consequently mRNA export (PubMed:27016737, PubMed:33689068). Within the TREX-2/AMEX-ORC complex, interacts with Orc6, (via C-terminus) with Orc3, and weakly interacts with Orc4 (PubMed:27016737, PubMed:33689068). However, another report found that the interaction with Orc3 is not direct, instead it is mediated via e(y)2 (Ref.7). Interacts with piwi (PubMed:28472469). Localizes to nuclear periphery, often in contact with the nuclear pore complex (NPC). Expressed in ovaries (at protein level). Detected in the testes and ovaries, with expression levels higher in oocytes than in testicular cells (at protein level). Detected in the testes and ovaries (at protein level). Detected in the testes. Detected in embryos (at protein level). Not detected in embryos (at protein level). Detected in embryos (at protein level). Belongs to the SAC3 family. Isoform A (xmas-2) and isoform B (xmas-1) were originally thought to be separate genes until a third longer transcript, isoform C, was identified that encompasses both ORFs and supports their existence as three alternatively spliced isoforms (PubMed:29779104). Although most of the functional information for this protein is attributed to isoform A/xmas-2 in the literature, it might also be relevant for isoform C and isoform B/xmas-1. Extended N-terminus. Extended N-terminus. Extended N-terminus.