Using
intradermal injection of a chimeric
RNA-
DNA oligonucleotide (RDO) or a single-stranded
oligonucleotide (ssODN) into murine skin, we attempted to make a dominant mutation (R94p) in the conserve alpha-helical domain of
keratin 17 (K17), the same mutation found in pachyononychia congenichia type 2 (PC-2) patients with phenotypes ranging from
twisted hair and multiple pilosebaceous
cysts. Both K17A-RDO and -ssODN contained a single base mismatch (CGC to CCC) to alter the normal K17 sequence to cause an amino acid substitution (R94P). The complexes consisting of
oligonucleotides and cationic
liposomes were injected to C57B1/6 murine skin at 2 and 5 day after birth. Histological examination of skin biopsies at postnatal day 8 from several mice showed consistent
twisted hair shafts or broken hair follicles at the sebaceous gland level and occasional
rupture of the hair bulb or
epidermal cyst-like changes. In the injected area, the number of full anagen hair follicles decrease by 50%. Injection of the control
oligonucleotide, identical to K17A-RDO but containing no mismatch to the normal sequence, did not result in any detectable abnormality. The frequency of gene alteration was lower than 3%, according to the restriction fragment length polymorphism (RFLP) analysis of the genomic
DNA isolated by dissection of hair follicles from slides. Although
intradermal injection of K17A-RDO or K17-ssODN caused a dominant mutation in K17 affecting hair growth and morphology, these phenotypic changes were transient either due to the compensation of K17 by other
keratins or the replacement of the mutated cells by normal surrounding cells during hair growth.