STAPHYLOCOCCAL CASSETTE CHROMOSOME GENE MecA variation in each scc mec type?

Question

[sinumolgeorge]

SCC MEC elements are 11 known to date. All 11 types contain MecA gene and orfX gene. But I confused about whether these gene sequences are varying in each type or remain same?

Answer 1

[Kevin Blighe]

The SCC-mec types are defined by the combinations of the ccr and mec operons, with an operon obviously being (in bacteria) genes in close proximity that can be transcribed together. In these operons, there are multiple genes, such as ccrA1, ccrA2, ..., mecA, mecB, etc.

The SCC-mec type configurations can be found at the International Working Group on the Staphylococcal Cassette Chromosome elements. There is another useful web-page here.

The orfX gene is still key, though, as it is the genomic locus at which SCC-mec becomes integrated, i.e., the integration site. Take a look here.

Kevin