Expression profile of active genes in human periodontal ligament and isolation of PLAP-1, a novel SLRP family gene

Gene. 2001 Sep 19;275(2):279-86. doi: 10.1016/s0378-1119(01)00683-7.


Periodontal ligament (PDL) is one of the most important tissues in maintaining the homeostasis of tooth and tooth-supporting tissue, periodontium. In this study, we investigated the expression profile of active genes in the human PDL obtained by collecting sequences with a 3'-directed cDNA library, which faithfully represents the composition of the mRNA population. We succeeded in obtaining a total of 1752 cDNA sequences by sequencing randomly selected clones and identified a total of 1318 different species as gene signatures (GS) by their sequence identity, 344 of which were known genes in the GenBank, and 974 of which were new genes. The resulting expression profile showed that collagen type I and type III were the most abundant genes and that osteogenesis-related proteins, such as SPARC/osteonectin and osteoblast specific factor 2, were highly expressed. By comparing the expression profile of PDL with 44 profiles similarly obtained with unrelated human cell/tissue, nine novel genes, which are probably expressed specifically in PDL, were discovered. Among them, we cloned a full-length cDNA of GS5096, which is frequently expressed in freshly-isolated periodontal tissue. We found that it encodes a novel protein, which is a new member of the class I small leucine-rich repeat proteoglycan family, and designated it PLAP-1 (periodontal ligament associated protein-1). PLAP-1 mRNA expression was confirmed in in vitro-maintained PDL cells and was enhanced during the course of the cytodifferentiation of the PDL cells into mineralized tissue-forming cells such as osteoblasts and cementoblasts. These findings suggest the involvement of PLAP-1 in the mineralized matrix formation in PDL tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Carrier Proteins / genetics*
  • Cell Division / genetics
  • Cells, Cultured
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • Extracellular Matrix Proteins
  • Gene Expression Profiling*
  • Gene Library
  • Humans
  • Molecular Sequence Data
  • Periodontal Ligament / cytology
  • Periodontal Ligament / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transcription, Genetic
  • Up-Regulation


  • ASPN protein, human
  • Carrier Proteins
  • DNA, Complementary
  • Extracellular Matrix Proteins
  • RNA, Messenger

Associated data

  • GENBANK/AY029191