EEF1DP3, alias eukaryotic translation elongation factor 1 delta pseudogene 3, is a pseudogene and it is located on chromosome 13 that is known to bring some putative oncogenes involved in cancer including the breast cancer type 2 (BRCA2) and the retinoblastoma (RB1) genes (Dunham et al., 2004). The related functional gene is the "eukaryotic translation elongation factor 1 delta" (EEF1D) that is located on chromosome 8 (8q24.3).
EEF1DP3 starts at 31,846,783 nt and ends at 31,959,584 from pter. It has a length of 112,802 bp and the current reference sequence is NC_000013.11 (Dunham et al., 2004). It is proximal to the relaxin family peptide receptor 2 (RXFP2) gene and FRY microtubule binding protein (FRY) gene. Curiously, closer to the genomic sequence of EEF1DP3 there is a promoter element that is located at -0.1 kb. This promoter element exercises its influence also on genes closer to EEF1DP3, i.e. FRY and RXFP2.
EEF1DP3 is classified as a transcribed unprocessed pseudogene. In the genomic sequence there are 4 non-coding exons.

EEF1DP3 pseudogene is transcribed and produces a long non-coding RNA (lncRNA) of 575 nt (Kimura et al., 2006) with a reference sequence NR_027062.1. It is still unknown if it is subjected to post-transcriptional modifications, such as 5-capping, 3-polyadenylation or splicing. However, other alternative transcripts are reported: EEF1DP3-001, a processed transcript of 1309 nt, EEF1DP3-002, a retained intron of 3283 nt and EEF1DP3-003, a transcribed unprocessed pseudogene of 782 nt (http://phase3browser.1000genomes.org). It seems that EEF1DP3 is overexpressed in heart, in particular in the left ventricle (https://www.genecards.org) and also expressed in normal trachea, liver, testis, kidney, bladder and brain (http://source-search.princeton.edu/). On the contrary, a low expression is detected in adrenal gland, colon and pituitary gland (https://amp.pharm.mssm.edu/Harmonizome/gene/EEF1DP3). It is known that lncRNAs, as pseudogenes as well as the others ncRNAs, may modulate the gene expression both at the transcriptional level, interacting with the promotor of parental gene o other genes, and post-transcriptional level, acting as microRNA decoys and so they may play key roles in cellular biological processes (Chan and Tay, 2018; Hu et al., 2018; Kovalenko and Patrushev, 2018). Nowadays, is still unknown the exact role of EEF1DP3 in healthy tissues.

EEF1DP3 seems to be able to produce a lncRNA but there are no proofs about the existence of a codified protein. However, is reported in some databases (UniProtKB; InterPro) a protein product also for this pseudogene, called "putative elongation factor 1-delta-like protein", alias EF1DL (accession number: Q658K8).
Until recently, it was believed that pseudogenes were not able to encode a protein, but recent transcriptomic and proteomic analyses seem to demonstrate not only the presence of pseudogene-derived transcripts but also of pseudogene-derived proteins (Chan and Tay, 2018; Kim et al., 2014; Djebali et al., 2012). Although it is still unclear if the protein EF1DL can be displayed or not, its presence should be not excluded. This protein should be 133 amino acids long and should have a molecular weight of 14,137 kDa and a theoretical pI of 5.94. Curiously, EF1DL shows 90% of identity with an uncharacterized protein (H2NJJ9_PONAB) of similar mass and length present in Sumatran orangutan (Pongo pygmaeus abelii) and linked to its chromosome 13.
Bioinformatic analysis of the comparison between EF1DL protein and eEF1D isoforms (pblast) revealed that there is an 85% of identity between EF1DL (1-90 aa) and a fragment of the long isoform of eEF1D (367-458 aa) and that is included a little portion of the second leucine-zipper domain of eEF1D. A similar result is obtained between EF1DL (1-90 aa) and the short form of eEF1D (1-92 aa) with the inclusion of a little portion of the unique leucine-zipper domain of the short form of eEF1D.
EF1DL could take a significant aspect in relation to cellular alterations observed in cancer that frequently juxtapose genomic elements next to strong promotor elements to produce unusual proteins that contribute to its malignant behavior and its aggressiveness. In fact, it is reported the involvement of EEF1DP3 in some genomic rearrangements and although there are no sufficient data yet to clarify these phenomena it cannot be excluded that EEF1DP3 can bring to a protein product after significative genomic alterations.