Biomedical subjects

Xinye Yin

Publications and source records attributed to Xinye Yin.

4 recordsLinked to original sources

PubMed2006

Thymocyte motility: mutants, movies and migration patterns.

Developing T cells are highly motile and undergo long-range migrations in the thymus as part of their developmental program. In the past two years, significant advances have been made in understanding the nature of the signals that control the entry of thymocyte progenitors into the thymus and the exit of mature thymocytes from the thymus. Progress has also been made in identifying the chemokine signals that control intrathymic migration patterns. In addition, the recent application of two-photon laser scanning microscopy has made it possible to make real-time observations of thymocytes within the three-dimensional environment of the thymus, and has shed new light on the relationship between positive selection and thymocyte migration.

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PubMed2006

Thymic microenvironments for T cell differentiation and selection.

The adult thymus provides a variety of specialized microenvironments that support and direct T cell differentiation and selection. In this review, we summarize recent advances in the understanding of the function of microenvironments in shaping a diverse T cell repertoire. In particular, we focus on how thymocytes move in and out of these specialized thymic compartments in response to homing signals, differential chemokine gradients and other factors that regulate T cell migration. In addition, we discuss the diverse developmental signals provided by these microenvironments that contribute to the generation of divergent T cell lineages.

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PubMed2005

Developmental regulation of the direct interaction between the intracellular loop of connexin 45.6 and the C terminus of major intrinsic protein (aquaporin-0).

The eye lens is dependent upon a network of gap junction-mediated intercellular communication to facilitate its homeostasis and development. Three gap junction-forming proteins are expressed in the lens of which two are in lens fibers, namely connexin (Cx) 45.6 and 56. Major intrinsic protein (MIP), also known as aquaporin-0 (AQP0), is the most abundant membrane protein in lens fibers. However, its role in the lens is not clear. Our previous studies show that MIP(AQP0) associates with gap junction plaques formed by Cx45.6 and Cx56 during the early stages of embryonic chick lens development but not in late embryonic and adult lenses. We report here that MIP(AQP0) directly interacts with Cx45.6 but not with Cx56. We further identified the intracellular loop of Cx45.6 as the interacting domain for the MIP(AQP0) C terminus. Surface plasmon resonance experiments indicated that the C-terminal domain of MIP(AQP0) interacts with two binding sites within the intracellular loop region of Cx45.6 with a K(D(app)) of 7.5 and 10.3 microm, respectively. The K(D(app)) for the full-length loop region is 7.7 microm. The cleavage at the intracellular loop of Cx45.6 was observed during lens development, and the C terminus of MIP(AQP0) did not interact with the loop-cleaved form of Cx45.6. Thus, the dissociation between these two proteins that occurs in the mature fibers of late lens development is likely caused by this cleavage. Finally this interaction had no impact on Cx45.6-mediated intercellular communication, suggesting that the Cx45.6-MIP(AQP0) interaction plays a novel unidentified role in lens fibers.

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PubMed2003

Stimulation of lens cell differentiation by gap junction protein connexin 45.6.

PURPOSE: The present study was undertaken to explore the roles gap junctions play in lens epithelial cell differentiation. METHODS: Recombinant retroviruses expressing three chick lens connexins (Cx)-Cx43, Cx45.6, and Cx56-were prepared and used to infect isolated chick lens primary cultures. The expression and distribution of proteins was determined using immunoblots and confocal immunofluorescence microscopy. Intercellular couplings were assessed by single cell microinjection and scrape-loading dye transfer, and cell proliferation was evaluated by [(3)H]thymidine labeling. RESULTS: Of the three lens connexins, only the cultures overexpressing exogenous Cx45.6 displayed the advancement of lens epithelial-fiber cell differentiation. The lentoids, a unique morphologic structure that is an indicative of lens fiber formation, were formed earlier in Cx45.6 overexpressed cultures; however, the rate of lens cell proliferation was not affected. The expression of the lens differentiation marker proteins, major intrinsic protein (MIP) and delta-crystallin, was also increased in Cx45.6-overexpressing cells. The cells overexpressing Cx45.6 displayed similar levels of intercellular couplings as did the controls. Moreover, exogenously expressed connexins were mostly colocalized with their endogenous counterparts and the overexpression of Cx45.6 had no impact on the expression of endogenous Cx43 and Cx56. CONCLUSIONS: These results suggest that Cx45.6 plays an important role in stimulating lens cell differentiation and fiber formation, which is different from the other lens connexins, Cx43 and Cx56. This stimulatory effect is independent of gap junction-mediated intercellular communication and lens cell proliferation.

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