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Sickle hemoglobin and α-thalassemia evolved as two of the most common human genetic polymorphisms because they confer protection against malaria. New evidence suggests that their effects may interfere with each other, raising questions about these hemoglobinopathies and their mechanisms of protection.
A new study shows that defects in SECIS-binding protein 2 (SBP2), a factor required for incorporation of selenium into proteins, produce alterations in thyroid hormone metabolism in humans but none of the other effects attributed to selenium deficiency or loss of selenoproteins. This finding suggests that SBP2 has a role in distinguishing between selenoproteins whose functions are essential and those with supporting roles in life and health.
An endosomal ferric reductase has long been implicated in the transferrin cycle. Identification of the gene mutated in a genetic anemia in mice uncovers a new family of ferric reductase enzymes involved in reduction of transferrin-bound iron.
Although RNA interference has become a useful genetic technique, effective and stable knock-down of vertebrate genes remains a challenge, especially in vivo. A new approach, which uses RNA polymerase II to generate small interfering RNAs, not only seems to be more effective than previous approaches but also allows tightly regulated RNA interference in culture and in vivo.