Neonatal rat submandibular gland protein SMG-A and parotid secretory protein are alternatively regulated members of a salivary protein multigene family.
Submandibular gland-A (SMG-A) is a major secretory product of the neonatal rat submandibular gland but is not synthesized by the acinar cells of the adult gland. The leucine-rich protein is a predominant product of the adult rat parotid gland. Preliminary data had indicated that the leucine-rich protein and SMG-A might be identical proteins whose expression was differently regulated in the parotid and submandibular salivary glands. cDNA clones encoding SMG-A and the leucine-rich protein were identified by homology to a major mouse parotid gland product, parotid secretory protein (PSP), and characterized. The leucine-rich protein shares extensive sequence homology with mouse PSP throughout its 5'-untranslated, protein coding and 3'-untranslated regions, prompting our suggestion that it should henceforth be referred to as rat PSP. SMG-A is more divergent, having greatest identity with rat and mouse PSP in its signal peptide and 3'-untranslated sequences. Transcripts homologous to SMG-A and rat PSP, but more closely related to SMG-A, were identified in rat sublingual gland by Northern blot analysis. These findings indicate that rat SMG-A and PSP arise from alternatively regulated members of a multigene family.
School of Dental and Oral Surgery, Columbia University, New York, New York 10032.
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D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D007150:Immunohistochemistry; D051379:Mice; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D005810:Multigene Family; D012313:RNA / Q000235:genetics; D051381:Rats; D012469:Salivary Glands / Q000378:metabolism / Q000648:ultrastructure; D012471:Salivary Proteins and Peptides / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
C511597:Bpifa2 protein, mouse; C511598:Bpifa2 protein, rat; D012471:Salivary Proteins and Peptides; C072564:Smgb Protein, rat; D012313:RNA; D004247:DNA