Crisanto Gutierrez

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Geminiviruses are DNA viruses which infect plants. They have a small genome and encode only a few proteins. Therefore, their DNA replication cycle relies largely on the use of cellular DNA replication proteins. The strategy used by geminiviruses to replicate their single-stranded DNA (ssDNA) genome consists of a first stage of conversion of ssDNA into(More)
Studies on the CDC6 protein, which is crucial to the control of DNA replication in yeast and animal cells, are lacking in plants. We have isolated an Arabidopsis cDNA encoding the AtCDC6 protein and studied its possible connection to the occurrence of developmentally regulated endoreplication cycles. The AtCDC6 gene is expressed maximally in early S-phase,(More)
Geminiviruses are plant DNA viruses with small genomes whose replication, except for the viral replication protein (Rep), depends on host proteins and, in this respect, are analogous to animal DNA tumor viruses, e.g. SV40. The mechanism by which these animal viruses create a cellular environment permissive for viral DNA replication involves the binding of a(More)
Geminiviruses encode a few proteins and depend on cellular factors to complete their replicative cycle. As a way to understand geminivirus-host interactions, we have searched for cellular proteins which interact with viral proteins. By using the yeast two-hybrid technology and the wheat dwarf geminivirus (WDV) RepA protein as a bait, we have isolated a(More)
Organogenesis in plants is almost entirely a postembryonic process. This unique feature implies a strict coupling of cell proliferation and differentiation, including cell division, arrest, cell cycle reactivation, endoreplication, and differentiation. The plant retinoblastoma-related (RBR) protein modulates the activity of E2F transcription factors to(More)
In eukaryotic cells, the function of DNA replication licensing components (Cdc6 and Cdt1, among others) is crucial for cell proliferation and genome stability. However, little is known about their role in whole organisms and whether licensing control interfaces with differentiation and developmental programs. Here, we study Arabidopsis thaliana CDT1, its(More)
The completion of the Arabidopsis genomic sequence offers the possibility to extract global information about regulatory mechanisms. Here, we describe a data mining strategy in combination with gene expression analysis to identify bona fide genes regulated by the E2F transcription factor. Starting with a genome-wide search of chromosomal sites containing(More)
Association of the retinoblastoma (Rb) protein with E2F transcription factors is central to cell cycle-specific gene expression and growth in animal cells. Whether Rb-E2F complexes are also involved in plant cell growth and differentiation is still unknown since E2F proteins have not yet been identified in plants. Here we report the isolation and(More)
Maintenance of genome integrity depends on histone chaperone-mediated chromatin reorganization. DNA replication-associated nucleosome deposition relies on chromatin assembly factor-1 (CAF-1). Depletion of CAF-1 in human cells leads to cell death, whereas in Arabidopsis (Arabidopsis thaliana), where it is involved in heterochromatin compaction and homologous(More)
Cell proliferation and cell fate decisions are strictly coupled processes during plant embryogenesis and organogenesis. In the Arabidopsis thaliana root epidermis, expression of the homeobox GLABRA2 (GL2) gene determines hair/non-hair cell fate. This requires signalling of positional information from the underlying cortical layer, complex transcriptional(More)