[Spatio-temporal expression of connexion (Cx) 40 and Cx45 in Cx43 knockout embryonic mouse hearts].
OBJECTIVE
To investigate the spatio-temporal expression of connexin (Cx) 40 and Cx45 genes in Cx43 knockout embryonic mouse hearts.


METHODS
Cx43 knockout heterozygous mice were raised. PCR was performed to identify genotypes of their offsprings. The homozygote (Cx43-/-) was used for study and the wild type (Cx43+/+) was used as control. Immuno-histochemistry was used to detect the Cx40 and Cx45 expression in different parts of the fetal hearts at the embryonic days (EDs) 10.5, 11.5, 12.5, 13.5, 14.5, and 15.5, respectively. SCIM microscopic image analytic system was used for quantitative analysis of staining intensity.


RESULTS
(1) Cx40 expression was detected in ventricles of Cx43+/+ fetal heart as early as ED10.5 with the intensity represented by A value of 8.6. Subsequently it was distributed in the atria and ventricles with the peak expression observed at ED14.5 (A value = 94.8), and faded afterwards. Less Cx40 expression was observed in the Cx43-/- fetal hearts as compared with Cx43+/+ although its expression pattern was similar in both groups. (2) Cx45 expression was detected in ventricles at ED 10.5 (A value = 20.0). It was subsequently distributed in the atria and ventricles with the peak expression observed at ED12.5 (A value = 49.6), and then faded. Less Cx45 expression was observed in the Cx43-/- fetal hearts as compared with Cx43+/+ although its expression pattern was similar as well in both groups.


CONCLUSIONS
Down-regulated expression of the genes Cx40 and Cx45 may be associated with the abnormal heart development in Cx43 knockout animals.
Xie
Li-Jian
LJ
Pediatric Heart Center, Children's Hospital of Fudan University, Shanghai 201102, China.
Huang
Guo-Ying
GY
Zhao
Xiao-Qing
XQ
Qi
Chun-Hua
CH
Peng
Tao
T
Zhou
Guo-Min
GM
D000818:Animals; D018031:Connexin 43 / Q000235:genetics; D017630:Connexins / Q000378:metabolism*; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism*; D000097003:Gap Junction alpha-5 Protein
D018031:Connexin 43; D017630:Connexins; D000097003:Gap Junction alpha-5 Protein; C082920:connexin 45