Mycoplasma Genitalium

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Mycoplasma Genitalium

• Genome Project

Sharndeep Kaur
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Genome

• Name Mycoplasma genitalium G-37
• Kingdom Bacteria
• Intermediate
• 1. Firmicutes2. Bacillus/Clostridium group3.
  Mollicutes
• 4.Mycoplasmataceae
• Genus Mycoplasma
• Species genitalium Strain G-37

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BackgroundMycoplasmas

• Mycoplasmas are members of the class Mollicutes
  and comprise a large group of bacteria which lack
  a cell wall, have small genomes, and a
  characteristically low
• G C content.
• These diverse organisms are parasites for a wide
  range of hosts including humans, animals,
  insects, plants, and cells grown in tissue
  culture.
• Mycoplasmas are of interest because they are
  believed to represent a minimal life form, having
  yielded to selective pressure to reduce genome
  size.

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BackgroundMycoplasma Genitalium

• Mycoplasma genitalium has the smallest genome
  size of 580 kb
• Lacks cell wall
• A gram-positive bacterium, is believed to be the
  cause of non-gonococcal urethritis (NGU)
• Causes reproductive-tract infections
• Urogenital tract may be the primary site of
  infection
• Exists in parasitic association with ciliated
  epithelial cells of primate genital and
  respiratory tracts
• Common name Tully JG et al. or G-37

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Background continues

• Mycoplasmas were initially mistaken for viruses
  because they can pass through 0.45 µm filters.
  This is attributable not only to their small
  size, but also the flexibility of their cell
  envelope.
• Only a few strains have been cultivated

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Background continues

• Analysis of rRNAs and tRNAs from mycoplasmas
  suggests that M. Genitalium arose through loss of
  genetic material from low GC gram-positive
  ancestors of the Lactobacillus-Clostridium branch
  of the phylogenetic tree
• Molecular characterization of the M. genitalium
  genome is hindered by the difficulty in applying
  classical genetics to the study of this and other
  mycoplasmas, and the lack of available
  auxotrophic mutants due to the requirement of
  this organism for complex media for growth in
  culture

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Why do biologists want to study this organism?

• Because it is considered to be the organism (not
  counting viruses) with the smallest genome

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Sequence information

• Sequenced by Fraser et al.
• Completed Jan 8, 2001
• Sequencing Center TIGR
• Funding Center DOE
• Publication PUBMED abstract

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Genome Stats

• The complete nucleotide sequence is 580,070 base
  pairs (smallest known genome of any free-living
  organism)
• A total of only 470 predicted coding regions were
  identified that include genes required for DNA
  replication, transcription and translation, DNA
  repair, cellular transport, and energy
  metabolism.
• Low GC content (32)
• UGA, normally a stop codon, encodes for the amino
  acid tryptophan.

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Genome Links

• www.Genome.ucsc.edu
• http//gnn.tigr.org/main.shtml
• http//www.ncbi.nlm.nih.gov
• http//www.tigr.org/tigr-scripts/CMR2/GenomePage3.
  spl?databasegmg
• http//www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd
  Retrievedbnucleotidelist_uids12044850doptGen
  Bank