A Family of Cyclin D Homologs from Plants Differentially Controlled by Growth Regulators and Containing the Conserved Retinoblastoma Protein Interaction Motif

1995 ◽  
Vol 7 (1) ◽  
pp. 85
Author(s):  
Rajeev Soni ◽  
Jeremy P. Carmichael ◽  
Zahid H. Shah ◽  
James A. H. Murray
Keyword(s):  
Growth Regulators ◽  
Protein Interaction ◽  
Retinoblastoma Protein ◽  
Cyclin D

Deletion of p16INK4 or amplification of CDK4 and cyclin D in human sarcoma: Complementary defects leading to inactivation of the retinoblastoma protein

1995 ◽  
Vol 84 (2) ◽  
pp. 145
Author(s):  
Jeanne-Marie Berner ◽  
Gunhild M. Mælandsmo ◽  
Anne Forus ◽  
Vivi Ann Flørenes ◽  
Johan Høie ◽  
...  
Keyword(s):  
Retinoblastoma Protein ◽  
Cyclin D ◽  
Human Sarcoma

scholarly journals Cyclin D1/Cdk4 regulates retinoblastoma protein-mediated cell cycle arrest by site-specific phosphorylation.

1997 ◽  
Vol 8 (2) ◽  
pp. 287-301 ◽  
Author(s):  
L Connell-Crowley ◽  
J W Harper ◽  
D W Goodrich
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Retinoblastoma Protein ◽  
Cyclin D ◽  
Cyclin Dependent Kinases ◽  
Cycle Arrest ◽  
Lxcxe Motif ◽  
Hyperphosphorylated Form

The retinoblastoma protein (pRb) inhibits progression through the cell cycle. Although pRb is phosphorylated when G1 cyclin-dependent kinases (Cdks) are active, the mechanisms underlying pRb regulation are unknown. In vitro phosphorylation by cyclin D1/Cdk4 leads to inactivation of pRb in a microinjection-based in vivo cell cycle assay. In contrast, phosphorylation of pRb by Cdk2 or Cdk3 in complexes with A- or E-type cyclins is not sufficient to inactivate pRb function in this assay, despite extensive phosphorylation and conversion to a slowly migrating "hyperphosphorylated form." The differential effects of phosphorylation on pRb function coincide with modification of distinct sets of sites. Serine 795 is phosphorylated efficiently by Cdk4, even in the absence of an intact LXCXE motif in cyclin D, but not by Cdk2 or Cdk3. Mutation of serine 795 to alanine prevents pRb inactivation by Cdk4 phosphorylation in the microinjection assay. This study identifies a residue whose phosphorylation is critical for inactivation of pRb-mediated growth suppression, and it indicates that hyperphosphorylation and inactivation of pRb are not necessarily synonymous.

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

Sign in / Sign up

Export Citation Format

Share Document