Characterization of DNA-hyaluronan matrix for sustained gene transfer.

DNA-Hyaluronan (DNA-HA) matrix formulations intended for use as gene delivery systems have been developed and their potential for delivering DNA encoding a model therapeutic cytokine, platelet-derived growth factor (PDGF), has been evaluated. The results of enzyme-mediated release kinetics studies suggested that the rate of DNA release from the DNA-HA matrices could be modulated by changing the DNA loading or the degree of crosslinking. SEM imaging of the DNA-HA matrix showed that it was gradually eroded by enzymatic action.

Human hair keratins.

Human hair keratins were among the first to be studied but it is only recently that sufficient information has been obtained to gain a basic biologic perspective of these proteins. Hair keratins are members of the intermediate filament family of proteins, yet are sufficiently divergent from epidermal keratins to warrant separate classification: type Ia and IIa ("hard"/hair keratins) and type Ib and IIb (epidermal and other "soft" keratins). As with hair keratins from other species, the human proteins may be distinguished from their epidermal counterparts by a relatively higher cysteine content, 7.

Transient expression of mouse hair keratins in transfected HeLa cells: interactions between "hard" and "soft" keratins.

Although it has been shown previously that an acidic (type I) "soft" keratin can interact with many basic (type II) "soft" keratins to form 10-nm intermediate filaments, it has been unclear whether "soft" keratins are compatible with the "hard" keratins typically found in hair and nail. To address this issue and to generate more structural information about hard keratins, we have isolated and sequenced a cDNA clone that encodes a mouse hair basic keratin (b4). Our sequence data revealed new information regarding the structural conservation of hard keratins as a group, being significantly different from soft keratins.

Differential expression of type I hair keratins.

The hair follicle provides an excellent system in which to study growth and differentiation. Hair keratins are useful tissue-specific molecular markers for these events. By comparing a second mouse Type I hair keratin cDNA clone, MHKA-2, with our previously described MHKA-1, we have been able to contrast the nucleotide sequences and corresponding deduced amino acid sequences of the smallest (mHa4) and the largest (mHa1) major Type I hair keratins.

Cloning and characterization of a mouse type I hair keratin cDNA.

A cDNA library was prepared from poly(A)-containing C57BL/6J mouse hair-root-enriched mRNA. The library was screened using a radiolabeled nucleic acid probe prepared from a sheep wool, Type I keratin cDNA clone (SWK2). Clone MHKA-1 was shown to contain a mouse hair, Type I keratin cDNA insert by positive hybridization-selection translation assay, and by the corresponding deduced amino acid sequence.