Terminology:
En-1[2ki] = 2ki, En-2 knock-in
En-1[Lki] = Lki, lacZ knock-in
En-1[hd] = hd, homeobox deletion
Figure 4. Analysis of brains from En-1[2ki/+2ki] mice. Intact brains and matched parasagittal sections through brains dissected from wild-type (A and B), En-1[hd/hd] (C and D), and En-1[2ki/+2ki] (E and F) newborn mice are shown. Also shown are matched sagittal sections through cerebellums of 6-week-old En-1[2ki/2ki] (G) and wild-type (H) mice. Sections were stained with hematoxylin and eosin.The deletion of colliculi (CL) and the cerebellum (Cb) are indicated.
Figure 2. Expression of integrated lacZ and En-2 sequences in embryos derived from lacZ-targeted and En-2 targeted ES cell lines, respectively. (a) and (B) show expression of lacZ oin chimeric embryos derived from aggregation of a lacZ-targeted ES cell line with a wild-type morula.
(A) A 9.0 dpc chimeric embryo stained with X-gal. Strong expression is seen in the mid-hindbrain region (M) and ventral ectoderm of the forelimb bud (Fl). The few somitic cells staining at this point are indicated by an arrow.
(B) An 11.5 dpc chimeric embryo stianed with X-gal. LacZ experssion is seen in the mid-hindbrain region, posterior hindbrain, spinal cord, somite-derived tissue (arrow), forelimb buds 9Fl) and hindlimb buds (Hl).
(C) In situ whole mounts of a one- to two-somite En-1[2ki/+] embryo and
(D) a wild type embryo probed with an En-2 specific antisense sequence. En-2 expression is seen in the naterior neural fold so the En-1[2ki/+] embryo but not the wild-type stage-matched control. This confirmed that the pattern of En-2 expression from the En-1[2ki] allele was like that of En-1.
(E) Protein immunoblot of protein extracts prepared from 9.5 dpc embryonic heads 9H0 and bodies (B), probed with Enhb-1 antiserum. lanes 1 and 2, wild type; lanes 3 and 4, En-1[2ki/+]; lanes 5 and 6, En-1[2ki/+2ki] embryos. En-2 protein is detected in both heads and bodies of En-1[2ki/+] and En-1[2ki/+2ki] embryos, but only in the heads of wild type embryos, and no En-1 protein is detected in En-1[2ki/+2ki] embryos.