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Molecular Cloning of emip , a Member of the Major Intrinsic Protein (MIP) Gene Family, Preferentially Expressed in Epidermal Cells of Barley Leaves
Author(s) -
Hollenbach Beate,
Dietz K. J.
Publication year - 1995
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1995.tb00516.x
Subject(s) - biology , epidermis (zoology) , gene , gene family , complementary dna , open reading frame , messenger rna , amino acid , microbiology and biotechnology , gene expression , molecular cloning , genetics , peptide sequence , anatomy
Cloning and characterization of a barley gene named emip is reported that encodes a member of the major intrinsic protein family. A λ‐unizap cDNA library synthesized from poly A + −mRNA of leaf epidermis was screened differentially with epidermis‐versus mesophyll‐derived probes. One of the clones epi 3‐2 was sequenced and further analyzed. The open reading frame of the full length clone codes for a polypeptide of 288 amino acids with a molecular mass of 30,634 Da exhibiting a high degree of homology with members of the major intrinsic protein family. Hydropathy analysis predicts six potential membrane‐spanning helices. mRNA levels were high in the growing zone of barley leaves and declined towards the tip of the fully expanded leaf blade. Expression was high in epidermal strips, lower in roots and very low in the leaf mesophyll. In order of decreasing response, wilting, salt shock and heat shock resulted in stimulated expression. mRNA levels remained low during slow salting up experiments. The expressional pattern suggests a role of EMIP in turgor regulation, particularly under stress.