HERV-H LTR Associating Protein 3 (HHLA3)

Human endogenous retrovirus (HERV) sequences are repetitive elements, derived from ancient germline retroviral infections, that have increased in copy number by further rounds of infection, retrotransposition, and/or duplication. The HERV-H family has been shown to play a role in the expression of a variety of adjacent genes.

The authors found 7 small EST clones from several different tissues for the HHLA3 gene. Northern blot analysis detected HHLA3 transcripts of approximately 0.9 to 1.0 kb in liver and kidney. RT-PCR analysis detected HHLA3 expression in all tissues examined. As with HHLA2, all identified HHLA3 ESTs utilized a HERV-H LTR as the polyadenylation signal. Three types of alternatively spliced HHLA3 transcripts that could encode proteins of 76, 121, or 153 amino acids were detected. The ORF for 2 of these transcripts continues into the LTR.