title: Intrinsic terminators in Mycoplasma hyopneumoniae transcription.
abstract: BACKGROUND
  Mycoplasma hyopneumoniae, an important pathogen of swine, exhibits a low guanine and cytosine (GC) content genome. M. hyopneumoniae genome is organised in long transcriptional units and promoter sequences have been mapped upstream of all transcription units. These analysis provided insights into the gene organisation and transcription initiation at the genome scale. However, the presence of transcriptional terminator sequences in the M. hyopneumoniae genome is poorly understood.
  
  
  RESULTS
  In silico analyses demonstrated the presence of putative terminators in 82% of the 33 monocistronic units (mCs) and in 74% of the 116 polycistronic units (pCs) considering different classes of terminators. The functional activity of 23 intrinsic terminators was confirmed by RT-PCR and qPCR. Analysis of all terminators found by three software algorithms, combined with experimental results, allowed us to propose a pattern of RNA hairpin formation during the termination process and to predict the location of terminators in the M. hyopneumoniae genome sequence.
  
  
  CONCLUSIONS
  The stem-loop structures of intrinsic terminators of mycoplasma diverge from the pattern of terminators found in other bacteria due the low content of guanine and cytosine. In M. hyopneumoniae, transcription can end after a transcriptional unit and before its terminator sequence and can also continue past the terminator sequence with RNA polymerases gradually releasing the RNA.
authors.affiliation: Centro de Biotecnologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. tefritsch@msn.com.
authors.forename: Tiago Ebert
authors.initials: TE
authors.lastname: Fritsch
authors.affiliation: Centro de Biotecnologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. franmaboni@gmail.com.
authors.forename: Franciele Maboni
authors.initials: FM
authors.lastname: Siqueira
authors.affiliation: Centro de Biotecnologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. irene@cbiot.ufrgs.br.|Departamento de Biologia Molecular e Biotecnologia, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P. 43421, C.P. 15005, Porto Alegre, RS, CEP 91501-970, Brazil. irene@cbiot.ufrgs.br.
authors.forename: Irene Silveira
authors.initials: IS
authors.lastname: Schrank
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D045705:Mycoplasma hyopneumoniae / Q000235:genetics* / Q000472:pathogenicity; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000235:genetics*; D013552:Swine / Q000235:genetics / Q000382:microbiology*; D061806:Transcription Termination, Genetic
chemical_list: D034741:RNA, Small Interfering; D012321:DNA-Directed RNA Polymerases