tailieunhanh - báo cáo hóa học:" Genome structure and transcriptional regulation of human coronavirus NL63"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí sinh học đề tài : Genome structure and transcriptional regulation of human coronavirus NL63 | Virology Journal BioMed Central Research Open Access Genome structure and transcriptional regulation of human coronavirus NL63 Krzysztof Pyrc Maarten F Jebbink Ben Berkhout and Lia van der Hoek Address Department of Human Retrovirology University of Amsterdam Meibergdreef 15 1105 AZ Amsterdam The Netherlands Email Krzysztof Pyrc - Maarten F Jebbink - Ben Berkhout - Lia van der Hoek - Corresponding author Published 17 November 2004 Received 29 October 2004 Accepted 17 November 2004 Virology Journal 2004 1 7 doi I743-422X-I-7 This article is available from http content 1 1 7 2004 Pyrc et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Two human coronaviruses are known since the 1960s HCoV-229E and HCoV-OC43. SARS-CoV was discovered in the early spring of 2003 followed by the identification of HCoV-NL63 the fourth member of the coronaviridae family that infects humans. In this study we describe the genome structure and the transcription strategy of HCoV-NL63 by experimental analysis of the viral subgenomic mRNAs. Results The genome of HCoV-NL63 has the following gene order 1a-1b-S-ORF3-E-M-N. The GC content of the HCoV-NL63 genome is extremely low 34 compared to other coronaviruses and we therefore performed additional analysis of the nucleotide composition. Overall the RNA genome is very low in C and high in U and this is also reflected in the codon usage. Inspection of the nucleotide composition along the genome indicates that the C-count increases significantly in the last one-third of the genome at the expense of U and G. We document the production of subgenomic sg mRNAs coding for the