EEF1E1-BLOC1S5 was identified for the first time by Prakash and colleagues in 2010 (Prakash et al, 2010). It starts at 8,013,567 nt and ends at 8,102,595 nt from pter with a length of 89,029 bp. It counts 7 exons and the current reference sequence is NC_000006.12. Near to the genomic sequence of EEF1E1-BLOC1S5 there is a strong promoter transcriptional element that is located at +1.0 kb. Enhancer transcriptional elements are located at +38.2 Kb and at +18.1 Kb respectively.

EEF1E1-BLOC1S5 counts 2,992 bp and it is a long non-coding RNA with reference sequence NR_037618.1. It derives from the read-through transcription between the neighboring EEF1E1 (eukaryotic translation elongation factor 1 epsilon 1) and MUTED (muted homolog) genes on chromosome 6. MUTED gene, alias BLOC1S5 (biogenesis of lysosomal organelles complex 1 subunit 5), is a component of BLOC-1 (biogenesis of lysosome-related organelles complex 1) complex that is involved in the biogenesis of organelles like melanosomes and platelet-dense granules.
It is a chimeric RNA, i.e. an RNA with a sequence derived from two genes and its transcriptional and post-transcriptional regulations could be the same as those of the other known-genes (He et al, 2018).
It was not possible to find experimentally a protein product for this chimeric RNA (Fagerberg et al, 2014), although in some databases is reported a theoretical protein product of 151 amino acids, with a predicted weight of 17,02 kDa and isoelectric point of 7.39 (https://www.uniprot.org/uniprot/C9J1V9; http://www.ensembl.org/Homo_sapiens/Transcript/ProteinSummary?g=ENSG00000265818;r=6:8015726-8102530;t=ENST00000397456). Therefore EEF1E1-BLOC1S5 is a candidate for nonsense-mediated mRNA decay (NMD) because it is unlikely to produce a protein product.

EEF1E1-BLOC1S5 ncRNA is transcribed (but not translated) widely in human tissues and normal cells. In memory B cells, it was found that the EEF1E1-BLOC1S5 is downregulated in the early gene expression (Day3-Day 0) following seasonal trivalent influenza vaccination in older individuals (Haralambieva et al, 2016)