NCBI Summary:
The protein encoded by this gene belongs to the heat shock protein 70 family. This gene uses alternative transcription start sites. A cis-acting segment found in the 5' UTR is involved in stress-dependent induction, resulting in the accumulation of this protein in the endoplasmic reticulum (ER) under hypoxic conditions. The protein encoded by this gene is thought to play an important role in protein folding and secretion in the ER. Since suppression of the protein is associated with accelerated apoptosis, it is also suggested to have an important cytoprotective role in hypoxia-induced cellular perturbation. This protein has been shown to be up-regulated in tumors, especially in breast tumors, and thus it is associated with tumor invasiveness. This gene also has an alternative translation initiation site, resulting in a protein that lacks the N-terminal signal peptide. This signal peptide-lacking protein, which is only 3 amino acids shorter than the mature protein in the ER, is thought to have a housekeeping function in the cytosol. In rat, this protein localizes to both the ER by a carboxy-terminal peptide sequence and to mitochondria by an amino-terminal targeting signal. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]
General function
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Comment
Expression regulated by
Comment
Ovarian localization
Cumulus
Comment
Expression profiles of select genes in cumulus-oocyte complexes from young and aged mares. Cox L et al. (2015) There is compelling evidence that oocytes from mares >18 years of age have a high incidence of inherent defects that result in early embryonic loss. In women, an age-related decrease in oocyte quality is associated with an increased incidence of aneuploidy and it has recently been determined that the gene expression profile of human oocytes is altered with advancing age. We hypothesised that similar age-related aberrations in gene expression occur in equine oocytes. Therefore, the aim of the present study was to compare gene expression profiles of individual oocytes and cumulus cells from young and aged mares, specifically evaluating genes that have been identified as being differentially expressed with advancing maternal age and/or aneuploidy in human oocytes. Expression of 48 genes was compared between 14 cumulus-oocyte complexes (COCs) from mares aged 3-12 years and 10 COCs from mares ≥18 years of age. Three genes (mitochondrial translational initiation factor 3 (IF3), heat shock transcription factor 5 (HSF5) and Y box binding protein 2 (YBX2)) were differentially expressed in oocytes, with all being more abundant in oocytes from young mares. Three genes (ADP-ribosylation factor-like 6 interacting protein 6 (ARL6IP6), BCL2-associated X protein (BAX) and hypoxia upregulated 1 (HYOU1)) were differentially expressed in cumulus cells, with all being more abundant in aged mares. The results of the present study confirm there are age-related differences in gene expression in equine COCs, which may be associated with the lower quality and decreased developmental competence of oocytes from aged mares.//////////////////