Data/hora: 21/09/2024 12:49:28

Biblioteca(s): 	Embrapa Gado de Leite.	
Data corrente: 	06/02/2017	
Data da última atualização: 	30/01/2023	
Autoria: 	ROCHA, L. C.; MITTELMANN, A.; HOUBEN, A.; TECHIO, V. H.	
Afiliação: 	Laiane Corsini Rocha, UFLA; ANDREA MITTELMANN, CNPGL; Andreas Houben, Leibniz Institute of Plant Genetics and Crop Plant Research, Germany; Vânia Helena Techio, UFLA.	
Título: 	Fragile sites of 45S rDNA of Lolium multiflorum are not hotspots for chromosomal breakages induced by X-ray.	
Ano de publicação: 	2016	
Fonte/Imprenta: 	Molecular Biology Reports, v. 43, n. 7, p. 659-665, 2016.	
Idioma: 	Português	
Conteúdo: 	Abstract Sites of 45S rDNA of Lolium are regions denominated fragile sites (FSs), constituting regions slightly stained with DAPI due to increased DNA unpacking in metaphasic chromosomes. Considered to be fragile regions in the genome, the FSs might be more responsive to induced breaks and result in chromosomal fragments and rearrangements, unless repairing mechanisms such as recombination or de novo telomere formation play a role at the break site of the DNA. Thus, this study aimed at investigating if SFs from Lolium are hotspots for the occurrence of breakages induced by X-ray and if they are regions favorable to synthesize new telomeres, using Hordeum vulgare as a comparative model. Lolium multiflorum and H. vulgare seedlings were irradiated with 20 and 50 Gy X-ray and evaluated one day following the irradiation and at 7-days intervals for a 28-days period, using FISH technique with 45S rDNA and Arabidopsistype telomere probes in order to investigate the presence of chromosomal breakages and new telomere formation. H. vulgare did not survive after a few days of irradiation due to the increased rate of abnormalities. L. multiflorum also exhibited chromosomal abnormalities following the exposure, yet over the 28-days trial it had a decrease in the chromosomal damage rate and formation of de novo telomere has not been detected along this time. Despite being considered to be fragile regions in the genome, the 45S rDNA sites of Lolium are not hotspots to chromosomal breakages after the induction of breakages.	
Palavras-Chave: 	Chromosomal abnormalities; De novo telomere formation; Ryegrass.	
Thesaurus Nal: 	barley; DNA repair; ionizing radiation.	
Categoria do assunto: 	F Plantas e Produtos de Origem Vegetal	
Registro original: 	Embrapa Gado de Leite (CNPGL)	
Exemplares: 	CNPGL - (23114-1) - UPC - AP - DD -  -  -  - DIS