Sample records for RUPTURA CROMOSOMICA (chromosome breakage)

Sample records 1 - 6 shown.


The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells

Carballo, Jesús A.; Pincheira, Juana; Torre, Consuelo de la

Digital.CSIC (Spain)


Roles of nibrin and ATM/ATR kinases on the G2 checkpoint under endogenous or radio-induced DNA damage

Marcelain, Katherine; Torre, Consuelo de la; González, Patricio; Pincheira, Juana

Digital.CSIC (Spain)


Merotelic attachments and non-homologous end joining are the basis of chromosomal instability

Alonso Guerrero, Astrid; Martínez-Alonso, Carlos; van Wely, Karel H.M.

Digital.CSIC (Spain)


Caracterización clínica, citogenética y molecular de un nuevo caso de síndrome de Nijmegen en Chile/ Clinical, cytogenetic and molecular characterization of a new case of Nijmegen breakage syndrome in Chile

Marcelain C, Katherine; Aracena A, Mariana; Be R, Cecilia; Navarrete S, Carmen Luz; Moreno H, Rosa; Santos A, Manuel; Pincheira V, Juana

Resumen en inglés The Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive disorder associated with microcephaly, immunodeficiency, chromosome instability and cancer proneness. The mutated gene that results in NBS codes for nibrin (Nbs1/p95), a DNA repair protein that is functionally linked to ATM, the kinase protein product of the gene responsible of ataxia-telangiectasia (A-T). We report the clinical, cytogenetic and molecular characterization of a second case of NBS in Chile d (mas) etected by us. The patient is a 7 years old Chilean boy from a consanguineous marriage, with microcephaly, immunodeficiency and acute non lymphocytic leukemia (ANLL). As NBS shares chromosomal and cellular features with A-T, the cytogenetic studies of this patient also included 3 A-T patients. Our results showed that the frequency of spontaneous and X rays induced chromosomal aberrations in NBS are higher than in A-T cells. DNA analysis revealed that the patient is homozygous for the Slavic mutation 657del5 in the NBS1 gene. This finding and the absence of nibrin in patient's cells, confirmed the clinical diagnosis of NBS in our patient (Rev Méd Chile 2004; 132: 211-18)

Scientific Electronic Library Online (Spanish)


Are aneuploidy and chromosome breakage caused by a CINgle mechanism?

Martínez-Alonso, Carlos; van Wely, Karel H.M.

Digital.CSIC (Spain)


Anormalidades Cromosómicas en la Microsporogénesis de Aloe Vera (L.) Burm. F. (Aloaceae)


Resumen en español El objetivo del presente trabajo es verificar la existencia de anormalidades cromosómicas asociadas a la baja fertilidad del polen en Aloe vera. El estudio se realizó a partir del aplastamiento de anteras inmaduras fijadas en etanol-acético y coloreadas con orceína. La viabilidad del polen se determinó en microcultivos de agar y sacarosa. Las anormalidades más frecuentes en meiosis I fueron: quiasmas persistentes entre homólogos grandes y desplazamiento precoz de c (mas) romosomas pequeños, uno o más puentes dicéntricos solitarios o acompañados con fragmentos acéntricos. En meiosis II, se observó la presencia ocasional de puentes y fragmentos, además de microsporas adicionales en la etapa de tétradas. Rupturas cromosómicas, errores de entrecruzamiento e inversión paracéntrica heterocigótica entre homólogos de mayor tamaño se discuten como posibles causas de las irregularidades meióticas observadas. Resumen en inglés The objective of this work is to verify the existence of chromosomic abnormalities associated to the low fertility of pollen in Aloe vera. The study was carried out starting from the squashing of immature anthers fixed in acetic-ethanol and stained with orceine. The viability of the pollen was determined in agar and sucrose microculture. The most frequent abnormalities in meiosis I were: chiasmata not finished between big homologous, and precocious displacement of small c (mas) hromosomes, one or more solitary or accompanied dicentric bridges with acentric fragments. In meiosis II, the occasional presence of bridges and fragments was observed, just as additional microspores. Chromosome breakage, crossing-over errors and heterozygotic paracentric inversion between greatest homologous are discussed like possible causes of the observed meiotic irregularities.

Scientific Electronic Library Online (Spanish)