The tumor suppressor gene liver kinase B1 （LKB1）, also called STKll, encodes a serine/threonine kinase. LKB1 plays crucial roles in cell differentiation, proliferation, and polarity. In this study, LKB1 conditional ...The tumor suppressor gene liver kinase B1 （LKB1）, also called STKll, encodes a serine/threonine kinase. LKB1 plays crucial roles in cell differentiation, proliferation, and polarity. In this study, LKB1 conditional knockout mice （LKB1pax2 CKO mice） were generated using Pax2-Cre mice to investigate the function of LKB1 in inner ear hair cells during early embryonic period. LKB1Pax2 CKO mice died perinatally. Immunofluorescence and scanning electron microscopy revealed that stereociliary bundles in LKB1Pax2 CKO mice were clustered and misoriented, respectively. Moreover, ectopic distribution of kinocilium bundles resulting from abnormal migration of kinocilium was observed in the mutant mice. The orientation of stereociliary bundles and the migration of kinocilia are critical indicators of planar cell polarity （PCP） of hair cells. LKB1 deficiency in LKB1Pax2 CKO mice thus disrupted hair cell planar polarity during embryonic development. Our results suggest that LKB1 is required in PCP formation in cochlear hair cells in mice.展开更多
Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mech...Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mechanism.To determine the role of Tprn in hearing,we generated Tprn-null mice by clustered regularly interspaced short palindromic repeat/Cas9 genome-editing technology from a CBA/CaJ background.We observed significant hearing loss and progressive degeneration of stereocilia in the outer hair cells of Tprn-null mice starting from postnatal day 30.Transmission electron microscopy images of stereociliary bundles in the mutant mice showed some stereociliary rootlets with curved shafts.The central cores of the stereociliary rootlets possessed hollow structures with surrounding loose peripheral dense rings.Radixin,a protein expressed at stereocilia tapering,was abnormally dispersed along the stereocilia shafts in Tprn-null mice.The expression levels of radixin andβ-actin significantly decreased.We propose that Tprn is critical to the retention of the integrity of the stereociliary rootlet.Loss of Tprn in Tprn-null mice caused the disruption of the stereociliary rootlet,which resulted in damage to stereociliary bundles and hearing impairments.The generated Tprn-null mice are ideal models of human hereditary deafness DFNB79.展开更多
基金This work was supported by grants from the National Basic Research Program （973） of China （No. 2014CB541703） the National Natural Science Foundation of China （Nos. 30871436, 30973297, 31171194, and 81670943）+1 种基金 the Shandong Provincial Science and Technology Key Program （No. 2009GG10002039） and the Shandong Provincial Natural Science Foundation of China Grant （No. ZR2013CQ041）.
文摘The tumor suppressor gene liver kinase B1 （LKB1）, also called STKll, encodes a serine/threonine kinase. LKB1 plays crucial roles in cell differentiation, proliferation, and polarity. In this study, LKB1 conditional knockout mice （LKB1pax2 CKO mice） were generated using Pax2-Cre mice to investigate the function of LKB1 in inner ear hair cells during early embryonic period. LKB1Pax2 CKO mice died perinatally. Immunofluorescence and scanning electron microscopy revealed that stereociliary bundles in LKB1Pax2 CKO mice were clustered and misoriented, respectively. Moreover, ectopic distribution of kinocilium bundles resulting from abnormal migration of kinocilium was observed in the mutant mice. The orientation of stereociliary bundles and the migration of kinocilia are critical indicators of planar cell polarity （PCP） of hair cells. LKB1 deficiency in LKB1Pax2 CKO mice thus disrupted hair cell planar polarity during embryonic development. Our results suggest that LKB1 is required in PCP formation in cochlear hair cells in mice.
文摘Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mechanism.To determine the role of Tprn in hearing,we generated Tprn-null mice by clustered regularly interspaced short palindromic repeat/Cas9 genome-editing technology from a CBA/CaJ background.We observed significant hearing loss and progressive degeneration of stereocilia in the outer hair cells of Tprn-null mice starting from postnatal day 30.Transmission electron microscopy images of stereociliary bundles in the mutant mice showed some stereociliary rootlets with curved shafts.The central cores of the stereociliary rootlets possessed hollow structures with surrounding loose peripheral dense rings.Radixin,a protein expressed at stereocilia tapering,was abnormally dispersed along the stereocilia shafts in Tprn-null mice.The expression levels of radixin andβ-actin significantly decreased.We propose that Tprn is critical to the retention of the integrity of the stereociliary rootlet.Loss of Tprn in Tprn-null mice caused the disruption of the stereociliary rootlet,which resulted in damage to stereociliary bundles and hearing impairments.The generated Tprn-null mice are ideal models of human hereditary deafness DFNB79.
