The vlhA loci of Mycoplasma synoviae are confined to a restricted region of the genome.

نویسندگان

  • Joanne L Allen
  • Amir H Noormohammadi
  • Glenn F Browning
چکیده

Mycoplasma synoviae, a major pathogen of poultry, contains a single expressed, full-length vlhA gene encoding its haemagglutinin, and a large number of vlhA pseudogenes that can be recruited by multiple site-specific recombination events to generate chimaeric variants of the expressed gene. The position and distribution of the vlhA pseudogene regions, and their relationship with the expressed gene, have not been investigated. To determine the relationship between these regions, a physical map of the M. synoviae genome was constructed using the restriction endonucleases SmaI, I-CeuI, BsiWI, ApaI and XhoI and radiolabelled probes for rrnA, recA and tufA. A cloned fragment encoding the unique portion of the expressed vlhA gene and two PCR products containing conserved regions of the ORF 3 and ORF 6 vlhA pseudogenes were used to locate the regions containing these genes on the map. The chromosome of M. synoviae was found to be 890.4 kb and the two rRNA operons were in the same orientation. Both the expressed vlhA gene and the vlhA pseudogenes were confined to the same 114 kb region of the chromosome. These findings indicate that, unlike Mycoplasma gallisepticum, in which the vlhA genes are located in several loci around the chromosome and in which antigenic variation is generated by alternating transcription of over 40 translationally competent genes, M. synoviae has all of the vlhA sequences clustered together, suggesting that close proximity is needed to facilitate the site-specific recombinations used to generate diversity in the expressed vlhA gene.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

The vlhA gene sequencing of Iranian Mycoplasma synoviae isolates

Mycoplasma synoviae expressed variable lipoprotein haemagglutinin (VlhA) is believed to play a major role in pathogenesis of the disease by mediating adherence and immune evasion. The aim of this study was sequencing Iranian M. synoviae isolates for the detection of nucleotide variation in the M. synoviae vlhA gene. Using oligonucleotide primers complementary to the single-copy conserved 5´ end...

متن کامل

Molecular characterization of Mycoplasma synoviae isolates from commercial chickens in Iran

Detection of Mycoplasma synoviae (MS) by culture and polymerase chain reaction (PCR) has been reported from commercial chicken farms in different provinces of Iran. In some reports the phylogenetic analysis of MS isolates based on 16S rRNA and variable lipoprotein hemagglutinin (vlhA) genes have been carried out. The PCR product containing partial 16S rRNA genes of Iranain isolates was sequence...

متن کامل

Molecular characterization of Mycoplasma synoviae isolated from broiler chickens of West Azarbaijan province by PCR of vlhA gene

Mycoplasma synoviae (MS) is a pathogen responsible for respiratory and locomotor disorders and causes major economic losses in poultry industry. Early and accurate diagnosis of MS infection plays a major role in control of the infection. This study was conducted to characterize Iranian field isolates of MS isolated from broiler chickens of West Azarbaijan province (Northwest of Iran), ...

متن کامل

Multigene families encoding the major hemagglutinins in phylogenetically distinct mycoplasmas.

Mycoplasma synoviae has two major membrane antigens, MSPA and MSPB, both of which are phase variable and which may be coordinately involved in adhesion of the organism to erythrocytes. A single gene (vlhA) from M. synoviae was characterized, and polypeptides were expressed from nonoverlapping 5' and 3' regions in Escherichia coli. The expression product of the vlhA 5' region reacted with specif...

متن کامل

Detection of Mycoplasma gallisepticum and Mycoplasma synoviae among Commercial Poultry in Khouzestan Province, Iran

Mycoplasmas are important  avian  pathogens,  which  can  cause  both  respiratory  disease  and  synovitis  in  poultry  that  result  in  considerable  economic  losses  to  the  poultry  industry  all  over  the  world.  The  aim  of  this  study  was  to  determine  the  prevalence  of  Mycoplasma  gallisepticum  and  Mycoplasma  synoviae  infections  among  commercial  poultry  flocks  in ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Microbiology

دوره 151 Pt 3  شماره 

صفحات  -

تاریخ انتشار 2005