MOLECULAR-CLONING AND ANALYSIS OF EXPRESSION OF THE LEISHMANIA-INFANTUM HISTONE H4 GENES

In the present work, we describe the sequence, organization and expres sion of histone H4 genes in the protozoan parasite Leishmania infantum . The predicted L. infantum histone H4 is a polypeptide of 100 amino a cids with a molecular mass of 11.5 kDa. Comparison of the amino acid s equence of Leishmania histone H4 with the rest of histone H4 sequences indicates that this is the most divergent sequence reported to date. The genomic distribution analysis of histone H4 genes indicates that t here must be up to seven gene copies. A single size-class histone H4 m RNA of 0.6 kb was detected, whose level dramatically decreases from lo garithmic to stationary phase. However, the Leishmania histone H4 mRNA s do not decrease in abundance following treatment with inhibitors of DNA synthesis,suggesting a regulation by a replication-independent mec hanism. (C) 1997 Elsevier Science B.V.