Tissue distribution of the secretory protein, SPLUNC1, in the human fetus.
We previously identified a tissue-specific gene, short palate, lung, and nasal epithelium clone 1 (SPLUNC1), in nasopharyngeal epithelial tissues. SPLUNC1 was differentially expressed in nasopharyngeal carcinoma. Bioinformatic analysis revealed that SPLUNC1 has the bactericidal permeability-increasing protein/lipid-binding protein (BPI/LBP) domain and a 19 amino acid signal peptide, which suggest that it is a secretory protein. Its precise cellular localization in the respiratory tract is mainly in mucous cells and ducts of submucosal glands. However, little is known about its expression pattern in various human tissues. We generated a highly specific antibody and analyzed its distribution in the human fetus by immunohistochemistry to more precisely determine SPLUNC1 protein localization in human tissues. The results were further validated by RT-PCR. Our results showed that SPLUNC1 protein is expressed at not only the serous glands and epithelium of the upper respiratory tract and digestive tract, but also in the oculi of human embryos. Interestingly, we also found positive staining in fetus adipose tissue, a result not previously reported in studies of adult human tissues. Western blot analysis detected a 24 kDa SPLUNC1 protein in the compounds of nasopharyngeal secretions. This secretory protein was also detected in saliva and tears. Our research suggests that SPLUNC1 protein may not only be an antimicrobial peptide that plays an important role in the maintenance of homeostasis in the upper respiratory tract, oculi, and alimentary tract, it may also be important in the development and lipid metabolism of the adipose tissue.
Zhou
Hou-De
HD
Cancer Research Institute, Central South University, Changsha, Hunan, 410078 China.
Fan
Song-Qin
SQ
Zhao
Jin
J
Huang
Dong-Hai
DH
Zhou
Ming
M
Liu
Hua-Ying
HY
Zeng
Zhao-Yang
ZY
Yang
Yi-Xing
YX
Huang
He
H
Li
Xiao-Ling
XL
Shen
Shou-Rong
SR
Li
Gui-Yuan
GY
D000273:Adipose Tissue / Q000196:embryology / Q000378:metabolism; D000328:Adult; D000595:Amino Acid Sequence; D000918:Antibody Specificity; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004064:Digestive System / Q000196:embryology / Q000378:metabolism; D005123:Eye / Q000196:embryology / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000378:metabolism*; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012137:Respiratory System / Q000196:embryology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
C485599:BPIFA1 protein, human; D017931:DNA Primers; D006023:Glycoproteins; D010750:Phosphoproteins; D012333:RNA, Messenger