Cellular localization and function of the antiviral protein, ovine Mx1 (oMx1): II. The oMx1 protein is a regulator of secretion in an ovine glandular epithelial cell line.
OBJECTIVE
Embryonic loss is a major contributor to infertility. Understanding factors affecting embryonic loss will help increase fertility.


METHODS
We investigated if ovine Mx1 (oMx1) mediated secretion by ovine glandular epithelial (oGE) cells using small interfering RNA (siRNA). Effects on secretion were examined through the conventional endoplasmic reticulum-Golgi pathway using beta2- microglobulin (beta2MG) as a marker, and interferon-stimulated gene 15 (ISG15) as a marker for unconventional secretion.


RESULTS
Mx1 siRNA reduced oMx1 mRNA levels at 12 and 24 hr after IFN-tau treatment (P < 0.05), without affecting levels of oMx2, ISG15, 2',5'-oligoadenylate synthetas or beta2MG. Mx1 siRNA reduced Mx1 protein levels at 48 and 120 hr after treatment (P < 0.05) and protein levels remained low at 120 hr. Transient oMx1 knock-down reduced secretion of oMx1 (P < 0.01). ISG15 protein in secretions was reduced without affecting intracellular levels (P < 0.05). Levels of beta2MG in secretions were not affected by Mx1 siRNA.


CONCLUSIONS
We showed that oMx1 protein is secreted by oGE cells and that reduction in oMx1 protein levels by siRNA reduced secretion of ISG15, but not beta2MG. Results support the hypothesis that oMx1 is a regulator of secretion through unconventional secretory pathway(s).
Toyokawa
Koji
K
Department of Animal and Veterinary Science, Center for Reproductive Biology, University of Idaho, Moscow, ID, USA.
Leite
Fabio
F
Ott
Troy L
TL
D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005786:Gene Expression Regulation; D007372:Interferons / Q000494:pharmacology; D064547:Myxovirus Resistance Proteins; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering; D012756:Sheep
D064547:Myxovirus Resistance Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D007372:Interferons; D019204:GTP-Binding Proteins