DNA double-strand break repair in Penaeus monodon is predominantly dependent on homologous recombination

Srivastava, Shikha and Dahal, Sumedha and Naidu, Sharanya J and Anand, Deepika and Gopalakrishnan, Vidya and Valappil, Rajendran Kooloth and Raghavan, Sathees C (2017) DNA double-strand break repair in Penaeus monodon is predominantly dependent on homologous recombination. In: DNA RESEARCH, 24 (2). pp. 117-128.

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Abstract

DNA double-strand breaks (DSBs) are mostly repaired by nonhomologous end joining (NHEJ) and homologous recombination (HR) in higher eukaryotes. In contrast, HR-mediated DSB repair is the major double-strand break repair pathway in lower order organisms such as bacteria and yeast. Penaeus monodon, commonly known as black tiger shrimp, is one of the economically important crustaceans facing large-scale mortality due to exposure to infectious diseases. The animals can also get exposed to chemical mutagens under the culture conditions as well as in wild. Although DSB repair mechanisms have been described in mammals and some invertebrates, its mechanism is unknown in the shrimp species. In the present study, we show that HR-mediated DSB repair is the predominant mode of repair in P. monodon. Robust repair was observed at a temperature of 30 degrees C, when 2 mu g of cell-free extract derived from hepatopancreas was used for the study. Although HR occurred through both reciprocal recombination and gene conversion, the latter was predominant when the bacterial colonies containing recombinants were evaluated. Unlike mammals, NHEJ-mediated DSB repair was undetectable in P. monodon. However, we could detect evidence for an alternative mode of NHEJ that uses microhomology, termed as microhomology-mediated end joining (MMEJ). Interestingly, unlike HR, MMEJ was predominant at lower temperatures. Therefore, the results suggest that, while HR is major DSB repair pathway in shrimp, MMEJ also plays a role in ensuring the continuity and stability of the genome.

Item Type:	Journal Article
Publication:	DNA RESEARCH
Additional Information:	Copy right for this article belongs to the OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	10 Jun 2017 04:39
Last Modified:	10 Jun 2017 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/57176

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