Abstract
Abstract: :
Purpose: Long time use of glucocorticoids may induce posterior subcapsular cataracts (PSC). This work was conducted to study the expression of p160 steroid receptor coactivator (SRCs) family members, including SRC1, GRIP1 (SRC2, Glucocorticoid Receptor–Interacting Protein 1,) and SRC3, in vertebrate ocular tissues. Methods: To determine the expression of SRCs at the RNA level, RT–PCR and later sequencing have been done using adult mouse lens total RNA. GRIP1 protein expression has been confirmed in 14 day embryo chicken lens by western blot. To determine the subcellular localization of GRIP1, immunostaining was performed on human lens and mouse eyes using an anti–GRIP1 antibody. The staining was viewed by confocal microscopy. Results: All three SRC family member mRNAs are transcribed in the mouse lens. At the protein level, GRIP1 protein was detected in the 14 day embryonic chicken lens by western blot. Immunostaining showed the localization of GRIP1 in the 11–week mouse lens, retina and cornea. In the lens, GRIP1 is present in both the cytoplasm and nucleus of lens epithelial and fiber cells, although it is mainly expressed in the epithelial cells. In the retina, GRIP1 is detectable in the processes of the inner plexiform layer and the cell bodies of the ganglion cell and the inner nuclear layers. However, there is no nuclear staining for GRIP1 in the retina. In the cornea, GRIP1 is located in both the cytoplasm and nucleus of the corneal epithelial and stroma cells. It is also present in the cytoplasm of endothelial cells. Conclusions: GRIP1 exists in vertebrate ocular tissue at both the RNA and protein level. It is localized in the nucleus and cytoplasm of different cell types in lens, retina and cornea. SRC1 and SRC3 mRNAs are also transcribed in mouse lens. Further analysis of the functions of these SRCs may provide insight into the mechanism of steroid cataract formation.
Keywords: transcription factors • gene/expression • receptors