OBJECTIVE PKC-ζ activation is a key signaling event for growth factor-induced β-cell replication in vitro. However, the effect of direct PKC-ζ activation in the β-cell in vivo is unknown. In this study, we examined the effects of PKC-ζ activation in β-cell expansion and function in vivo in mice and the mechanisms associated with these effects. RESEARCH DESIGN AND METHODS We characterized gluc...

A major proportion of plant biomass is derived from the activity of the cambium, a lateral meristem responsible for vascular tissue formation and radial organ enlargement in a process termed secondary growth. In contrast to our relatively good understanding of the regulation of primary meristems, remarkably little is known concerning the mechanisms controlling secondary growth, particularly how...

Cyclin E1 (formerly called cyclin E) and the recently described cyclin E2 belong to the family of E-type cyclins that operate during the G(1)/S phase progression in mammalian cells. The two E-cyclins share a catalytic partner, cyclin-dependent kinase 2 (CDK2), and activate their associated kinase activities at similar times during cell cycle progression. Despite these similarities, it is unknow...

Kaposi's sarcoma-associated herpesvirus (KSHV) has a key etiological role in development of Kaposi's sarcoma (KS). v-Cyclin is a KSHV-encoded homologue to D-type cyclins that associates with cellular cyclin-dependent kinase 6 (CDK6). v-Cyclin promotes S-phase entry of quiescent cells and has been suggested to execute functions of both D- and E-type cyclins. In this study, expression of v-cyclin...

The 34-kilodalton cyclin-dependent kinase, p34cdk4, is a major catalytic subunit of mammalian D-type cyclins, which act during the G1 phase of the cell cycle to enforce the decision of cells to enter S phase. A murine complementary DNA clone was used to clone the cognate human CDK4 gene, which was localized to human chromosome 12, band q13, by fluorescence in situ hybridization. Because this ch...

Phosphorylation is a key event in cell cycle control, and dysregulation of this process is observed in many tumors, including those associated with specific inherited neoplasia syndromes. We have shown previously that patients with the autosomal dominant tumor predisposition Carney complex carry inactivating mutations in the PRKAR1A gene, which encodes the type 1A regulatory subunit of protein ...

Mammalian D-type cyclins are growth factor-regulated, delayed early response genes that are presumed to control progression through the G1 phase of the cell cycle by governing the activity of cyclin-dependent kinases (cdks). Overexpression of mouse cyclin D1 in serum-stimulated mouse NIH-3T3 and rat-2 fibroblasts increased their rates of G o to Sand GIto S-phase transit by several hours, leadin...

BACKGROUND Human herpesvirus 8 (HHV8) appears to be the agent responsible for Kaposi sarcoma. The mechanism remains undetermined but may involve cell cycle regulating genes including D type cyclins which are pivotal in cell cycle progression. Recent HHV8 genetic analysis has revealed the presence of a v-cyclin which is homologous to D type cyclins. AIMS First, to assess whether there is an in...

Seed development in Arabidopsis is characterized by stereotypical division patterns, suggesting that coordinated control of cell cycle may be required for correct patterning and growth of the embryo and endosperm. D-type cyclins (CYCD) are key cell cycle regulators with roles in developmental processes, but knowledge regarding their involvement in seed development remains limited. Here, a famil...