Open AccessBasic proline‐rich proteins of murine parotid glands
Author(s) -
BANNISTER Andrew J.,
DIVECHA Nullin,
ASHMORE Michael,
McDONALD Charles J.
Publication year - 1989
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1989.tb14734.x
Subject(s) - isoprenaline , proline , trichloroacetic acid , parotid gland , secretion , in vitro , messenger rna , endocrinology , chemistry , medicine , biochemistry , biology , microbiology and biotechnology , amino acid , stimulation , pathology , gene
Five major basic polypeptides with characteristics typical of proline‐rich proteins, accumulated in parotid glands after long term isoprenaline treatment of Balb C mice. They were studied by two‐dimensional gel electrophoresis and designated B1°, B2′°, B2°, B3° and B4° on the basis of pI‐dependent mobility. They were not observed in the glands of normal mice and were precipitated when glands were homogenized in 10% trichloroacetic acid unlike the three isoprenaline‐induced proline‐rich proteins of murine parotid glands reported previously. Isoprenaline induced six proline‐rich in vitro translation products which were absent normally. Four of these species had pI‐dependent mobilities almost identical to B1°, B2°, B3° and B4°, indicating not only precursor/product relationships, but also that isoprenaline induced the accumulation of the proteins by regulating the mRNA. Identical salivary counterparts of the basic glandular proline‐rich proteins were not detected whereas a series of smaller and more basic isoprenaline‐induced polypeptides were observed in saliva (major speices B1 s –B4 s ). The glandular proline‐rich proteins were secreted from parotid tissue in vitro and the data indicate that proline‐rich proteins are synthesised as precursors and processed into salivary form in the parotid glands after secretion. The relationships between the B‐type in vitro translation products, parotid gland precursors and salivary proteins were also confirmed immunologically.