The Tcl1 oncogene defines secondary hair germ cells differentiation at catagen-telogen transition and affects stem-cell marker CD34 expression.
Overexpression of the TCL1 gene family plays a role in the onset of T-cell leukemias in mice and in humans. The Tcl1 gene is tightly regulated during early embryogenesis in which it participates in embryonic stem (ES)-cells proliferation and during lymphoid differentiation. Here, we provide evidences that Tcl1 is also important in mouse hair follicle (HF) and skin homeostasis. We found that Tcl1(-/-) adult mice exhibit hair loss, leading to alopecia with extensive skin lesions. By analysing Tcl1 expression in the wild-type (wt) skin through different stages of hair differentiation, we observe high levels in the secondary hair germ (HG) cells and hair bulges, during early anagen and catagen-telogen transition phases. The loss of Tcl1 does not result in apparent skin morphological defects during embryonic development and at birth, but its absence causes a reduction of proliferation in anagen HFs. Importantly, we show the that absence of Tcl1 induces a significant loss of the stem-cell marker CD34 (but not alpha6-integrin) expression in the bulge cells, which is necessary to maintain stem-cell characteristics. Therefore, our findings indicate that Tcl1 gene(s) might have important roles in hair formation, by its involvement in cycling and self-renewal of transient amplifying (TA) and stem-cell (SC) populations.
Ragone
G
G
Molecular Oncology Laboratory, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy.
Bresin
A
A
Piermarini
F
F
Lazzeri
C
C
Picchio
M C
MC
Remotti
D
D
Kang
S-M
SM
Cooper
M D
MD
Croce
C M
CM
Narducci
M G
MG
Russo
G
G
D000505:Alopecia / Q000209:etiology; D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis*; D002454:Cell Differentiation; D018859:Hair Follicle / Q000196:embryology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D012867:Skin / Q000473:pathology; D013234:Stem Cells / Q000502:physiology*
D018952:Antigens, CD34; D011518:Proto-Oncogene Proteins; C490393:Tcl1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt