|
|
|
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
|
Fig. 6. E4BP4 reduces programmed cell death of motoneurons in vivo. (A) Scheme
showing the electroporation protocol and areas used for TUNEL quantification.
(B) High-magnification view of an E5 chicken embryo expressing GFP in ventral
roots (arrows), used as a criterion for selecting embryos in which motoneurons
were successfully electroporated. (C) Images of one representative spinal cord
co-electroporated with GFP and E4BP4, and viewed at E7 using transmission
(left panel) or fluorescence (centre panel) optics. In the right panel, the
zone of GFP expression has been traced onto the transmission image. The spinal
cord has been opened and dorsal regions appear at the left and right of the
images, while the midline runs vertically through the tissue. The position of
the ventral horns is visualised by the TUNEL signal, as only motoneurons
undergo PCD at this stage. Within the area of GFP expression, three zones are
apparent. In zone 1, E4BP4 is expressed dorsally to motoneurons and does not
affect the TUNEL signal (asterisk). In zone 2, E4BP4 expressed in the motor
columns reduces the number of TUNEL-positive cells compared with the
contralateral side (compare black and open arrowheads). In zone 3, E4BP4
expressed in motoneurons not already undergoing cell death does not trigger
apoptosis (arrow). (D) In each area indicated in A, numbers of TUNEL-positive
neurons at E7 were expressed as a percentage of the value on the contralateral
side in each spinal cord. Values are shown for embryos electroporated with GFP
alone (green bars) or with GFP and E4BP4 (orange bars). Means±s.e.m.
are indicated; numbers of embryos analysed are indicated above the bars.
Overexpression of E4BP4 reduces the number of dying motoneurons by 45%,
whereas GFP alone has no effect.
|
