Enhanced E-cadherin expression and increased calcium-dependent cell-cell adhesion in human T-cell leukemia virus type I Tax-expressing PC12 cells.
Human T-cell leukemia virus type I (HTLV-I) Tax protein induces the expression of host cellular genes, some of which are crucial in cell proliferation and differentiation. We examined the mechanisms by which HTLV-I Tax protein induces phenotypic changes in PC12 cells. We demonstrated that the HTLV-I Tax gene induces epithelioid changes and increases cell-cell contact in PC12 cells. No change in the expression of the neural cell adhesion molecule was observed between HTLV-I Tax-expressing PC12 cells and PC12 cells transfected with a control plasmid. However, HTLV-I Tax-expressing PC12 cells demonstrated a marked change in the abundance and distribution of E-cadherin, which was concentrated at regions of cellular contact and accompanied by changes in calcium-dependent cell adhesion. Although E-cadherin is expressed at low levels in PC12 and PC12 transfected with a control plasmid cells, the steady state level of E-cadherin in tax-expressing PC12 cells increases significantly, apparently as a result of regulation at the transcriptional level. Diminished expression of Tax protein in Tax-expressing PC12 cells exposed to antisense oligonucleotides for the Tax gene suppresses E-cadherin expression and decreases cell-cell adhesion. These findings imply that HTLV-I Tax protein enhanced E-cadherin expression modulates calcium-dependent cell-cell adhesion mechanisms.
Department of Molecular and Laboratory Medicine, Kagoshima University, Japan.
I
I
Kitajima
K
K
Kawahara
N
N
Hanyu
H
H
Shin
T
T
Tokioka
Y
Y
Soejima
J
J
Tsutsui
M
M
Ozawa
T
T
Shimayama
I
I
Maruyama
D000818:Animals; D001483:Base Sequence; D015820:Cadherins / Q000096:biosynthesis*; D002118:Calcium / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D016356:Gene Products, tax / Q000096:biosynthesis*; D015368:Human T-lymphotropic virus 1; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense; D016716:PC12 Cells; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats
D015820:Cadherins; D016356:Gene Products, tax; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D002118:Calcium