Transcript Mycoplasma Genitalium

Mycoplasma Genitalium
Genome Project
Sharndeep Kaur
Genome





Name: Mycoplasma genitalium G-37
Kingdom: Bacteria
Intermediate
1. Firmicutes
2. Bacillus/Clostridium group
3. Mollicutes
4.Mycoplasmataceae
Genus: Mycoplasma
Species: genitalium Strain G-37
Background
Mycoplasmas
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.
Background
Mycoplasma 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 nongonococcal 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
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
Background
continues


Analysis of rRNAs and tRNAs from mycoplasmas
suggests that M. Genitalium arose through loss of
genetic material from low G+C 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
Why do biologists want to study
this organism?

Because it is considered to be the
organism (not counting viruses) with the
smallest genome
Sequence information
Sequenced by Fraser et al.
Completed: Jan 8, 2001
Sequencing Center: TIGR
Funding Center: DOE
Publication: PUBMED abstract
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 G+C % content (32%)
UGA, normally a stop codon, encodes for the amino acid
tryptophan.
Genome Links
www.Genome.ucsc.edu
http://gnn.tigr.org/main.shtml
http://www.ncbi.nlm.nih.gov
http://www.tigr.org/tigrscripts/CMR2/GenomePage3.spl?database=gmg
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?c
md=Retrieve&db=nucleotide&list_uids=1204485
0&dopt=GenBank