Cyclin A downregulation and p21(cip1) upregulation correlate with GATA-6-induced growth arrest in glomerular mesangial cells.
The GATA-6 transcription factor is reported to be expressed in vascular myocytes. Because glomerular mesangial cells (GMCs) and vascular myocytes have similar properties, we examined whether GATA-6 was expressed in cultured GMCs and whether overexpression of GATA-6 induced cell cycle arrest in GMCs, using a recombinant adenovirus that expresses GATA-6 (Ad GATA-6). GATA-6 expression in GMCs was downregulated when quiescent GMCs were stimulated by serum to reenter the cell cycle. [(3)H]thymidine uptake was inhibited in GMCs infected with Ad GATA-6 in a dose- and time-dependent manner. The expression of cyclin A protein was decreased and that of the cyclin-dependent kinase inhibitor p21(cip1) was increased in GMCs infected with Ad GATA-6. Although the expression of p21(cip1) transcripts did not change remarkably, p21(cip1) protein was stabilized in GMCs infected with Ad GATA-6, suggesting a post-transcriptional regulation of p21(cip1) expression. Northern blot analysis showed that expression of the cyclin A transcript was decreased in Ad GATA-6-infected cells, whereas this decrease of cyclin A was not observed in GMCs derived from p21(cip1) null mice. Our results demonstrate that GATA-6 is endogenously expressed in GMCs and that overexpression of GATA-6 can induce cell cycle arrest. Our results also show that GATA-6-induced cell cycle arrest is associated with inhibition of cyclin A expression and p21(cip1) upregulation. Finally, our results indicate that the GATA-6-induced suppression of cyclin A expression depends on the presence of p21(cip1).
Nagata
D
D
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Suzuki
E
E
Nishimatsu
H
H
Yoshizumi
M
M
Mano
T
T
Walsh
K
K
Sata
M
M
Kakoki
M
M
Goto
A
A
Omata
M
M
Hirata
Y
Y
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology; D015152:Blotting, Northern; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D019925:Cyclin A / Q000235:genetics / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D050993:GATA6 Transcription Factor; D015870:Gene Expression / Q000187:drug effects; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation
D001798:Blood Proteins; C493956:CDKN1A protein, human; C493958:Cdkn1a protein, rat; D018797:Cell Cycle Proteins; D019925:Cyclin A; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495892:Cdk2 protein, rat; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D013936:Thymidine