The sld mutation is specific for sublingual salivary mucous cells and disrupts apomucin gene expression.
NFS/N-sld mice harbor a spontaneous autosomal recessive mutation, sld (sublingual gland differentiation arrest) and histologically display attenuated mucous cell expression in sublingual glands (Hayashi et al. Am J Pathol 132: 187-191, 1988). Because altered serous demilune cell expression is unknown, we determined the phenotypic expression of this cell type in mutants. Moreover, we evaluated whether absence of glycoconjugate staining in 3-day-old mutant glands is related to disruption in apomucin gene expression and/or to posttranslational glycosylation events. Serous cell differentiation is unaffected, determined morphologically and by serous cell marker expression (PSP, parotid secretory protein; and Dcpp, demilune cell and parotid protein). Conversely, apical granules in "atypical" exocrine cells of mutant glands are PSP and mucin negative, but contain abundant SMGD (mucous granule marker). Age-related appearance of mucous cells is associated with expression of apomucin gene products, whereas SMGD expression is unaltered. "Atypical" cells thus appear specified to a mucous cell fate but do not synthesize mucin glycoproteins unless selectively induced postnatally, indicating the sld mutation disrupts apomucin transcriptional regulation and/or decreases apomucin mRNA stability.
Fallon
M A
MA
University of Rochester Medical Center, Center for Oral Biology and the Department of Pharmacology and Physiology, Rochester, New York 14642-8611, USA.
Latchney
L R
LR
Hand
A R
AR
Johar
A
A
Denny
P A
PA
Georgel
P T
PT
Denny
P C
PC
Culp
D J
DJ
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D005260:Female; D005752:Gastric Mucins / Q000096:biosynthesis* / Q000235:genetics*; D005786:Gene Expression Regulation / Q000235:genetics*; D005808:Genes, Recessive; D006031:Glycosylation; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009092:Mucous Membrane / Q000737:chemistry / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D016296:Mutagenesis; D011499:Protein Processing, Post-Translational / Q000235:genetics; D011817:Rabbits; D051381:Rats; D013361:Sublingual Gland / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure
D005752:Gastric Mucins; C053366:apomucin