Characterization of the mouse transforming growth factor α gene : Its expression during eyelid development and in waved 1 tissues

• Published in: Cell growth & differentiation Vol. 7; no. 9; pp. 1271 - 1282
• Main Authors: BERKOWITZ, E. A, SEROOGY, K. B, SCHROEDER, J. A, RUSSELL, W. E, EVANS, E. P, RIEDEL, R. F, PHILLIPS, H. K, HARRISON, C. A, LEE, D. C, LUETTEKE, N. C
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01-09-1996
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Brain Chemistry; Chromosome Aberrations; Cornea - metabolism; DNA, Complementary - genetics; Epithelium - chemistry; Epithelium - pathology; Eyelids - embryology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; Genes. Genome; Mice; Mice, Knockout; Mice, Mutant Strains; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Mutation - physiology; Organ Specificity; Promoter Regions, Genetic - genetics; Receptor, Epidermal Growth Factor - genetics; RNA, Messenger - analysis; Sequence Analysis, DNA; Transcription, Genetic; Transforming Growth Factor alpha - genetics; Eyelid; Nucleotide sequence; Transcription promoter; Rodentia; Primary structure; Hair follicle; Gene organization; Vertebrata; Mammalia; Mouse; Development; Transforming growth factor α; Structural analysis
• ISSN: 1044-9523; 2377-0732

The spontaneous mouse waved 1 (wa1) mutation is allelic with the transforming growth factor alpha (TGF-alpha) gene and produces phenotypes similar to those of TGF-alpha knockout mice. Here, we show that TGF-alpha mRNA and protein levels are measurable in wa1 tissues but reduced 5- to 30-fold relative to wild type. Because the wa1-coding sequence is identical to that of the normal mRNA, wa1 is not a null mutation. Nuclear run-on analyses revealed decreased transcription of the TGF-alpha gene in wa1 tissues, but the sequence of a 3.2-kb 5' flanking fragment containing the promoter was unaltered. Moreover, pulsed field gel electrophoresis analysis did not reveal alterations within 750 kb upstream or 350 kb downstream of the gene, and chromosome 6 was karyotypically normal. Hence, we speculate that the wa1 mutation may be subtle and/or reside at a greater distance from the TGF-alpha gene. TGF-alpha deficiency elicits a spectrum of variably penetrant eye anomalies in wa1 and knockout mice that are associated with open eyes at birth. We found that late-gestation wa1 and TGF-alpha-null embryos display a significant delay in eyelid closure, although the eyes of most embryos fuse prior to birth. In situ hybridization localized TGF-alpha expression to the advancing margins of the eyelid epithelium and epidermal growth factor receptor expression throughout the eyelid and corneal epithelia. These results suggest that eye problems observed in TGF-alpha-deficient adult mice arise from premature exposure and trauma to open eyes during or following parturition.