Author/Editor		Kordiš, Dušan; Bdolah, Avner; Gubenšek, Franc
Title		Positive Darwinian selection in Vipera palaestinae phospholipase A2 genes is unexpectedly limited to the third exon
Type		članek
Source		Biochem Biophys Res Commun
Vol. and No.		Letnik 251, št. 2
Publication year		1998
Volume		str. 613-9
Language		eng
Abstract		The venom of Vipera palaestinae contains a twocomponent toxin, consisting of an acidic phospholipase A2 (PLA2) and a basic protein. Here we report the cloning and sequence analysis of the complete V. palaestinae PLA2 genes. Since in all Viperidae PLA2 multigene families the 5' and 3' flanking regions are highly conserved, we designed oligonucleotide primers that allow amplication of the whole PLA2 multigene famility in a single step. The structural organization of both genes is the same as in the Vipera ammodytes PLA2 multigene family, there being five exons separated by four introns. Comparison of V. palaestinae PLA2 genes with other Viperidae PLA2 genes has shown that the structural organizationof the genes and the nucleotide sequence of all introns and flanking regions are highly conserved, whereas the third exon clearly shows a higher number of amino acid replacements, an indication of positive Darwinian selection. The positive Darwinian selection is surprisingly limited to the third exon, in contrast to other Viperidae PLA2 genes, where it is present in all mature protein coding exons.
Descriptors		VIPER VENOMS PHOSPHOLIPASES A MULTIGENE FAMILY SELECTION (GENETICS) EXONS VIPERIDAE PROMOTER REGIONS (GENETICS) INTRONS DNA PRIMERS SEQUENCE ANALYSIS, DNA POLYMERASE CHAIN REACTION