蛋白激酶A的表达及其在调节牙囊中成牙相关基因方面的潜在作用。

Yao Shaomian, Wise Gary E

Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana 70803, USA.

Med Sci Monit. 2003 May;9(5):BR160-7.

BACKGROUND

Tooth eruption requires the chronological expression of a series of genes in the dental follicle (DF). Protein kinase A (PKA) is a major phosphorylation pathway in the cells, and may regulate the expression of tooth eruption genes.

MATERIAL/METHODS: In vivo, we studied the expression of the regulatory (R) and catalytic (C) subunits of PKA in the DF of newborn rats. In vitro, dental follicle cells (DFC) were treated with a specific PKA inhibitor, and then the gene expression of monocyte chemotactic protein-1 (MCP-1), colony-stimulating factor-1 (CSF-1) and parathyroid hormone-related protein receptor (PTHrP-R) was determined. Cells also were treated with either phorbol-12-myristate-13-acetate or dibutyryl-cAMP, and the gene expression for RI alpha, RI beta, RII alpha and RII beta of PKA was examined.

RESULTS

The results indicate that RI alpha of PKA is the predominant subunit in the DF with steady expression from days 1 to 11 postnatally. In contrast, expression of the RI beta, RII alpha, RII beta subunits are progressively reduced over this time period. However, there is a sharp decline of RI beta expression at postnatal day 3. The expression of the C subunits slightly decreases at days 3 and 5 with a greater decrease at day 7 postnatally. The specific PKA inhibitor reduces MCP-1 gene expression and translation, as well as moderately reducing CSF-1 and PTHrP-R expression.

CONCLUSIONS

The reduction of the RI beta subunit in the rat DF at day 3 may result in an elevated PKA activity to trigger the maximal burst of gene expression of MCP-1 and CSF-1 seen at this time.

背景

牙齿萌出需要牙囊（DF）中一系列基因按时间顺序表达。蛋白激酶A（PKA）是细胞内主要的磷酸化途径，可能调节牙齿萌出相关基因的表达。

材料/方法：在体内，我们研究了新生大鼠牙囊中PKA调节（R）亚基和催化（C）亚基的表达。在体外，用特异性PKA抑制剂处理牙囊细胞（DFC），然后测定单核细胞趋化蛋白-1（MCP-1）、集落刺激因子-1（CSF-1）和甲状旁腺激素相关蛋白受体（PTHrP-R）的基因表达。还用佛波醇-12-肉豆蔻酸酯-13-乙酸酯或二丁酰环磷腺苷处理细胞，并检测PKA的RIα、RIβ、RIIα和RIIβ的基因表达。

结果

结果表明，PKA的RIα是牙囊中主要的亚基，在出生后第1天至第11天表达稳定。相比之下，在此时间段内RIβ、RIIα、RIIβ亚基的表达逐渐降低。然而，RIβ的表达在出生后第3天急剧下降。C亚基的表达在出生后第3天和第5天略有下降，在第7天下降更明显。特异性PKA抑制剂降低MCP-1基因的表达和翻译，同时适度降低CSF-1和PTHrP-R的表达。