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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

GENE EXPRESSION REGULATORS <em>lin-11</em> AND <em>let-711</em>, IN MODULATING THE RATE OF AGING AND LIFESPAN, IN <em>C. elegans</em>.

Yeshi Jamling, Tseten 01 January 2011 (has links)
lin-11 and let-711 are early-developmental gene expression regulators with no previously known roles in aging regulation. Yet, they show strong aging-correlated expression profiles (Lund, Tedesco et al. 2002). lin-11 is strongly upregulated in very old worm populations, and let-711 is progressively downregulated in aging worm populations. Microarray studies were performed to identify their genome-wide targets, which were then subjected to further lifespan and genetic analysis to investigate their role in C. elegans aging. The results indicate that the target pools of both lin-11 and let-711 are enriched for aging genes, since a significant number of tested genes increased lifespan. This enrichment of aging genes in their target pools provides strong evidence that lin-11 and let-711 are indeed regulating the expression of aging genes in adult C. elegans. The data suggests that increased lin-11 expression as well as reduced let-711 expression may be promoting longevity by downregulating the insulin/IGF-1 pathway. Decreasing let-711 may also be contributing to longevity by downregulating the germline signaling pathway. K11E4.2, R53.5, C49A9.2 and Y82E9BR.5 are four genes from the lin-11 target pool, whose knockdown produced increases inlifespan. These are unannotated genes, and the details of their roles in aging regulation are not known at this point. ins-3 expression was downregulated two-fold upon knockdown of lin-11, suggesting the possible involvement of lin-11 in regulation of the insulin/IGF-1 pathway. An RNAi construct for ins-3 was not available and it is not known whether loss of ins-3 leads to lifespan extension. let-711 knockdown resulted in an almost four-fold reduction in pdk-1 expression. pdk-1 is an integral part of the insulin/IGF-1 pathway and its knockdown by RNAi extended lifespan. Four other genes from the let-711 target pool that increased lifespan, cdc-25.1, gna-2, meg-1 and ooc-3, all have germline specific functions. The extensions in lifespan generated by these genes were completely dependent on DAF-16. Furthermore, for gna-2, meg-1 or ooc-3, they were independent of DAF-2. These results agree with previously established mechanisms for germline regulation of aging, suggesting the involvement of let-711 in regulating the germline-signaling pathway.

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