Differential expression of alpha A- and alpha B-crystallin during murine ocular development.
OBJECTIVE
To compare the temporal and spatial expression patterns of alpha A- and alpha B-crystallin mRNA during ocular development.


METHODS
Tissue samples from embryonic day 9.5 (E9.5) through postnatal day 14 were collected from FVB/N strain mice. The specimens were fixed in paraformaldehyde, histologically processed, and assayed for alpha A- and alpha B-crystallin mRNA expression by in situ hybridization.


RESULTS
During ocular development, alpha B-crystallin transcripts are present in the lens placode at E9.5. Transcripts of alpha A-crystallin are first observed in the lens cup at E10 to 10.5. During subsequent development of the lens, alpha A crystallin transcripts are most abundant in the fiber cells, and alpha B crystallin mRNA is preferentially expressed in epithelial cells. Transcripts of alpha A-crystallin were detected only in the lens. In contrast, alpha B-crystallin transcripts are present in retinal pigment epithelium, optic nerve, extraocular muscle, iris, ciliary body, cornea, and several nonocular sites, such as heart and nasal epithelium.


CONCLUSIONS
Transcription of alpha B-crystallin precedes the expression of alpha A-crystallin during murine ocular development. Furthermore, the patterns of alpha A- and alpha B-crystallin expression in the lens are distinctive: alpha A is upregulated and alpha B is downregulated during prenatal fiber cell differentiation. These results indicate that the alpha-crystallin genes are not identically regulated either within or outside the lens.
Robinson
M L
ML
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Overbeek
P A
PA
D000818:Animals; D003459:Crystallins / Q000096:biosynthesis* / Q000235:genetics; D015536:Down-Regulation; D005123:Eye / Q000196:embryology* / Q000378:metabolism; D005260:Female; D005318:Fetal Heart / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D007908:Lens, Crystalline / Q000196:embryology / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009297:Nasal Mucosa / Q000378:metabolism; D009666:Nose / Q000196:embryology; D012333:RNA, Messenger / Q000096:biosynthesis*; D015854:Up-Regulation
D003459:Crystallins; D012333:RNA, Messenger