On the high conservation of the human c-myc first exon

Several hypotheses have been proposed to explain the role that the human c-myc 1st exon is thought to play in the regulation of the expression of the c-myc protein. One of these hypotheses, based on sequencing data showing an open reading frame overlapping that exon, predicts the existence of a protein most probably involved in the regulation of the expression of the c-myc protein. However, mainly because several other published sequences are devoided of such an ORF, this hypothesis did not retain much attention. In this paper, we present two additional sequences fully identical to the 1st exon region sequence we previously published, and discuss the implication of such a high degree of conservation for the human c-myc 1st exon.