TY - JOUR
T1 - Molecular characterization and evolution of the sprr family of keratinocyte differentiation markers encoding small proline-rich proteins
AU - Gibbs, Susan
AU - Fijneman, Remond
AU - Wiegant, Joop
AU - van Kessel, Ad Geurts
AU - van de Putte, Piet
AU - Backendorf, Claude
PY - 1993/6
Y1 - 1993/6
N2 - SPRR genes (formerly SPR) encode a novel class of polypeptides (small pr oline rich proteins) that are strongly induced during differentiation of human epidermal keratinocytes in vitro and in vivo. Recently we found that the N- and C-terminal domains of these proteins show strong sequence homology to loricrin and involucrin, suggesting that SPRR proteins constitute a new class of cornified envelope precursor proteins. Here we show that SPRR proteins are encoded by closely related members of a gene family, consisting of two genes for SPRR1, approximately seven genes for SPRR2, and a single gene for SPRR3. All SPRR genes are closely linked within a 300-kb DNA segment on human chromosome 1 band q21-q22, a region where the related loricrin and involucrin genes have also been mapped. The most characteristic feature of the SPRR gene family resides in the structure of the central segments of the encoded polypeptides that are built up from tandemly repeated units of either eight (SPRR1 and SPRR3) or nine (SPRR2) amino acids with the general consensus *K*PEP**. Sequencing data of the different members, together with their clustered chromosomal organization, strongly suggest that this gene family has evolved from a single progenitor gene by multiple intra- and intergenic duplications. Analysis of the different SPRR subfamilies reveals a gene-specific bias to either intra- or intergenic duplication. We propose that a process of homogenization has acted on the different members of one subfamily, whereas the different subfamilies appear to have diverged from each other, at the levels of both protein structure and gene regulation.
AB - SPRR genes (formerly SPR) encode a novel class of polypeptides (small pr oline rich proteins) that are strongly induced during differentiation of human epidermal keratinocytes in vitro and in vivo. Recently we found that the N- and C-terminal domains of these proteins show strong sequence homology to loricrin and involucrin, suggesting that SPRR proteins constitute a new class of cornified envelope precursor proteins. Here we show that SPRR proteins are encoded by closely related members of a gene family, consisting of two genes for SPRR1, approximately seven genes for SPRR2, and a single gene for SPRR3. All SPRR genes are closely linked within a 300-kb DNA segment on human chromosome 1 band q21-q22, a region where the related loricrin and involucrin genes have also been mapped. The most characteristic feature of the SPRR gene family resides in the structure of the central segments of the encoded polypeptides that are built up from tandemly repeated units of either eight (SPRR1 and SPRR3) or nine (SPRR2) amino acids with the general consensus *K*PEP**. Sequencing data of the different members, together with their clustered chromosomal organization, strongly suggest that this gene family has evolved from a single progenitor gene by multiple intra- and intergenic duplications. Analysis of the different SPRR subfamilies reveals a gene-specific bias to either intra- or intergenic duplication. We propose that a process of homogenization has acted on the different members of one subfamily, whereas the different subfamilies appear to have diverged from each other, at the levels of both protein structure and gene regulation.
UR - http://www.scopus.com/inward/record.url?scp=0027243148&partnerID=8YFLogxK
U2 - https://doi.org/10.1006/geno.1993.1240
DO - https://doi.org/10.1006/geno.1993.1240
M3 - Article
C2 - 8325635
SN - 0888-7543
VL - 16
SP - 630
EP - 637
JO - Genomics
JF - Genomics
IS - 3
ER -