The pea lectin gene family contains only one functional gene

Abstract

Molecular hybridization experiments have shown that the pea genome contains four regions which hybridize with pea lectin cDNA (Kaminski, Buffard, and Strosberg, 1986. Plant Science 46, 111-116). The complete organization of the pea lectin gene family was investigated. Four partial EcoRI genomic libraries were screened with a lectin cDNA (pPS 15-50) covering the entire coding region. Four positive recombinant phages, λI 101, λI 52, λIII 51 and λIV 22, were isolated and the DNA sequences of the subclones, designated respectively PSL1, PSL2, PSL3 and PSL4, were determined. PSL2, PSL3 and PSL4 are incomplete genes; the presence of several stop codons in the correct reading frames indicate that these genes cannot code for a functional lectin protein. The sequences of PSL1 and pPS 15-50 have identical coding regions. The pea lectin gene has no intervening sequences and is flanked at its 5' region by a sequence containing an exceptionally high A+T content (73%). Eucaryotic consensus sequences such as a TATA box and a polyadenylation signal are also found in the flanking regions of the PSL1 clone.