Restricted distribution of integrin beta 6 mRNA in primate epithelial tissues.
Integrins are cell adhesion receptors that mediate cell-extracellular matrix and cell-cell interactions. Each integrin consists of two glycoprotein subunits (alpha and beta). We have previously described a novel integrin beta-subunit, beta 6, which is expressed in cultured epithelial cells. beta 6 can associate with alpha v to form the fibronectin-binding heterodimer alpha v beta 6. Here we report the tissue distribution of beta 6 integrin mRNA determined by in situ hybridization of a beta 6 cRNA probe with representative frozen tissue sections from a rhesus monkey tissue bank. We detected beta 6 mRNA exclusively in epithelial cells. However, beta 6 mRNA expression varied greatly among different epithelia. High levels of beta 6 mRNA were found only in two very specialized epithelial cell types: a portion of the kidney tubule epithelium, termed macula densa, and the endometrial epithelium of secretory phase uterus. In the endometrium, beta 6 expression was highest in the differentiated epithelium of functional layer glands, suggesting that beta 6 expression can be regulated in a differentiation-dependent manner. beta 6 expression may also depend on the stage in the estrous cycle, since we found much lower beta 6 mRNA levels in a specimen of proliferative phase endometrium. Epithelium in several other tissues, including salivary gland ducts, gall bladder, and epididymis, contained detectable levels of beta 6 mRNA, albeit much lower than in macula densa and endometrium. In other epithelia, including skin and lung, beta 6 mRNA was undetectable. Taken together, these results suggest that in normal adult primates beta 6 expression is regulated in a cell type-specific manner, restricted to a few epithelial tissues.
Breuss
J M
JM
Department of Medicine, University of California, San Francisco 94143-0854.
Gillett
N
N
Lu
L
L
Sheppard
D
D
Pytela
R
R
D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D004717:Endometrium / Q000737:chemistry; D004848:Epithelium / Q000737:chemistry; D005260:Female; D017403:In Situ Hybridization; D039641:Integrin beta Chains; D016023:Integrins / Q000235:genetics*; D007684:Kidney Tubules / Q000737:chemistry; D008253:Macaca mulatta; D008297:Male; D009928:Organ Specificity; D015347:RNA Probes; D012333:RNA, Messenger / Q000032:analysis*; D014018:Tissue Distribution
D039641:Integrin beta Chains; D016023:Integrins; D015347:RNA Probes; D012333:RNA, Messenger; C072170:integrin beta6