Expression and significance of wingless-type MMTV integration site family, member 5A/receptor tyrosine kinase-like orphan receptor 2 in the rat dental follicle / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the expression of wingless-type MMTV integration site family, member 5A (Wnt5A)/receptor tyrosine kinase-like orphan receptor 2 (Ror2) signal in the dental follicle cells during the normal eruption of the teeth as well as to explore the relationship between the expression of dental follicle cells and the formation of mature osteoclasts and eruption of the teeth.</p><p><b>METHODS</b>The mandibulars of 1-13 d old SD rats were separated to observe the growth and develop-ment of the teeth and alveolar bone through hematoxylin-eosin(HE) staining. Ror2 and Wnt5A expressions in rat dental follicle were also observed through immunohistochemistry. Dental follicle cells from the lower first intact molar germs of 5-6-day old SD rats were separated and cultured.</p><p><b>RESULTS</b>On the second day after birth, the dental follicle began to differentiate into periodontal tissues, but no obvious changes were observed in the alveolar bone one to three days after birth. On the fourth day, the number of osteoclasts increased significantly. The results of immunohistochemistry showed that Wnt5A was not significantly expressed in rat dental follicle tissues before the fourth day, but positive expression was expressed in the next day and continued to express to thirteenth days. Ror2 was expressed in the rat dental follicle at postnatal days 1-3, but weak expression was found in days 4-13.</p><p><b>CONCLUSIONS</b>Wnt5A and Ror2 expressions in the process of tooth eruption have specific time distributions, suggesting that these expressions may participate in the regulation of the eruption of the teeth.</p>

ROR1, an embryonic protein with an emerging role in cancer biology

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a member of the ROR family consisting of ROR1 and ROR2. RORs contain two distinct extracellular cysteine-rich domains and one transmembrane domain. Within the intracellular portion, ROR1 possesses a tyrosine kinase domain, two serine/threonine-rich domains and a proline-rich domain. RORs have been studied in the context of embryonic patterning and neurogenesis through a variety of homologs. These physiologic functions are dichotomous based on the requirement of the kinase domain. A growing literature has established ROR1 as a marker for cancer, such as in CLL and other blood malignancies. In addition, ROR1 is critically involved in progression of a number of blood and solid malignancies. ROR1 has been shown to inhibit apoptosis, potentiate EGFR signaling, and induce epithelial-mesenchymal transition (EMT). Importantly, ROR1 is only detectable in embryonic tissue and generally absent in adult tissue, making the protein an ideal drug target for cancer therapy.

ROR2 gene is associated with risk of non-syndromic cleft palate in an Asian population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The receptor tyrosine kinase-like orphan receptor 2 (ROR2) gene has been recently shown to play important roles in palatal development in animal models and resides in the chromosomal region linked to non syndromic cleft lip with or without cleft palate in humans. The aim of this study was to investigate the possible association between ROR2 gene and non-syndromic oral clefts.</p><p><b>METHODS</b>Here we tested 38 eligible single-nucleotide polymorphisms (SNPs) in ROR2 gene in 297 non-syndromic cleft lip with or without cleft palate and in 82 non-syndromic cleft palate case parent trios recruited from Asia and Maryland. Family Based Association Test was used to test for deviation from Mendelian inheritance. Plink software was used to test potential parent of origin effect. Possible maternally mediated in utero effects were assessed using the TRIad Multi-Marker approach under an assumption of mating symmetry in the population.</p><p><b>RESULTS</b>Significant evidence of linkage and association was shown for 3 SNPs (rs7858435, rs10820914 and rs3905385) among 57 Asian non-syndromic cleft palate trios in Family Based Association Tests. P values for these 3 SNPs equaled to 0.000068, 0.000115 and 0.000464 respectively which were all less than the significance level (0.05/38 = 0.0013) adjusted by strict Bonferroni correction. Relevant odds ratios for the risk allele were 3.42 (1.80 - 6.50), 3.45 (1.75 - 6.67) and 2.94 (1.56 - 5.56), respectively. Statistical evidence of linkage and association was not shown for study groups other than non-syndromic cleft palate. Neither evidence for parent-of-origin nor maternal genotypic effect was shown for any of the ROR2 markers in our analysis for all study groups.</p><p><b>CONCLUSION</b>Our results provided evidence of linkage and association between the ROR2 gene and a gene controlling risk to non-syndromic cleft palate.</p>

Identification of a recurrent mutation in the ROR2 gene in a Chinese family with brachydactyly type B / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the disease-causing mutation in a Chinese family with brachydactyly type B (BDB).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood samples of family members. Exons 8 and 9 of the ROR2 gene were amplified by polymerase chain reaction (PCR) and sequenced directly. Furthermore, the PCR products showing mutation were cloned into pMD18T vector and the insert fragments were sequenced.</p><p><b>RESULTS</b>A 1398-1399 insA heterozygous mutation was detected in the patient. This mutation had been found in German families with BDB.</p><p><b>CONCLUSION</b>To the authors' knowledge, it is the first report on identification of the ROR2 pathogenic mutation in Chinese patients with BDB.</p>