Finally, the presence of tail-to-tail, instead of expected head-to-head, orientation of paired reads at duplicated region ends in the three newly sequenced strains indicates that the repeated copies are organized in tandem.
Here the advantage of a head-to-head orientation of both promoters becomes clear, as it places them in close vicinity and a loss of the resistance marker would provide an accurate harbinger of the forthcoming silencing within the expression cassette.
Emma Reed Emma Reed is the head of sexual orientation and transgender policy for the Government Equalities Office.
The future studies may systematically address safety of the HBE and identify the safest, most effective head of bed orientation for patients on invasive mechanical ventilation.
Evidence that the clusters have arisen by means of gene duplication events is provided by the conservation of gene order, intergenic distance and the head-to-head orientation of the α and β subunit genes in each cluster.
All three known HSL isoforms exhibit a homodimeric structure with a head-to-head orientation of the two monomers, and with two major structural domains in each monomer.
The Latimeria v1r01 and v1r02 genes, on the other hand, share the head-to-head orientation of their teleost counterparts ora1 and ora2, but lie much farther apart, with about 100 kb distance between v1r01 and v1r02.
31.6% (390/1236) of all two-gene segments have head-to-head orientation, and 48.8% (1521/3118) of all head-to-head pairs lie within a segment, indicating that while head-to-head orientation may facilitate coexpression, it is neither required nor diagnostic (Additional file 3: Table S3).
Head-to-head orientation causes inversion of the DNA between the two sites, whereas head-to-tail orientation results in the excision of the intervening DNA sequence, an irreversible reaction due to the loss of the excised product.
We show now with a supplementary figure that the head-to-head orientation and the relative orientation of head-domains to coiled coil stalks in the nine-membered ring are similar to those observed in the two other crystal structures presented in our manuscript that do not crystallize as rings (97-320 FE construct and WT 97-274 construct).
