Organization of the major latex protein gene family in opium poppy.

Opium poppy latex contains a group of laticifer-specific, low-molecular-weight polypeptides called major latex proteins (MLPs). Here we describe a new member of the MLP gene family (gMLP 22) which shares 79.6% nucleotide and 84.6% amino acid sequence identity with previously isolated clones. DNA gel blot analysis indicates that the MLPs are encoded by at least eight genes which are divided into two subfamilies. The expression pattern for each subfamily, as seen in RNA gel blots, appears to be identical and laticifer-specific.