Metals of antiquity Metals of antiquity The metals of antiquity are the seven metals which humans had identified and found use for in prehistoric times: gold, silver, copper, tin, lead, iron, and mercury. These seven are the metals from which the modern world was forged; until the discovery of arsenic in the 13th century, these were the only known elemental metals, compared to the 86 known today. The metals of antiquity generally have low melting points, with iron being the exception. While all the metals of antiquity but tin and lead occur natively, only gold and silver are commonly found as the native
Poxvirus AX element late mRNA cis-regulatory element element. Poxvirus AX element late mRNA cis-regulatory element The Poxvirus AX element late mRNA family represents a "cis"-regulatory element present at the 3' end of poxvirus late ATI mRNA and is known as the AX element. The AX element is involved in directing the efficient production and orientation-dependent formation of late RNAs. It is likely that this element directs the endonucleolytic cleavage of the transcript. It has been shown that the F17R late mRNA transcript which is also cleaved is also likely to share a common factor in their mechanism despite a lack of any obvious similarity in its cis-regulatory