Abstract
Abstract: :
Purpose: mCDT–22 is a novel cDNA isolated from a mouse cornea cDNA library. This study is to characterize the mCDT–22 full–length cDNA and examine its expression during mouse eye development. Methods: Automate DNA sequencing was used to obtain the full–length cDNA sequence. DNA sequence search analysis was done via NCBI Blast analysis program. Northern blotting and in situ hybridizations were carried out to examine the CDT–22 mRNA distribution in various adult mouse tissues and mouse embryos during development. Western blotting and immunohistochemical analysis using anti–CDT–22 antibody were performed to characterize its cellular location and tissue distribution. Results: The mCDT–22 cDNA clone contains 2954 base pairs with 161bp 5’–untranslated region, 1818bp central region encoding 606 amino acids, and 758 bp 3’–untranslated region. Blast analysis showed that mCDT22 shared 97% homology with a Homo sapiens hypothetical protein MGC2742 (MGC2742), mRNA (#NM_023938) isolated from human small cell lung carcinoma cell line. Northern blotting hybridization showed that mCDT22 mRNA expresses in mouse tissues derived from surface and neural ectoderm including eye, brain, skin, tongue, lung, kidney, liver, stomach, intestine, and esophagus, etc, but not in the tissues without epithelium such as heart and muscle. Western blotting using a rabbit anti–mCDT22 antibody identified a 65 kD polypeptide. Finally, immunohistochemical staining revealed that mCDT22 is located on the cytoplasmic membrane and only expresses in the basal layers of the adult corneal epithelium but not in the limbus. Interestingly, CDT22 protein also expresses in the inner nuclear and ganglian layers of the retina. Conclusions:mCDT22 mRNA is the homologue of the human hypothetical protein MGC2742. The abundant expression of the mCDT–22 in epithelial basal layer of the cornea and ganglia layer of the neural retina may suggest a special differentiation function to this protein.
Keywords: cornea: basic science • gene/expression • grouping and segmentation