Mutations in Radial Spoke Head Protein Genes RSPH9 and RSPH4A Cause Primary Ciliary Dyskinesia with Central-Microtubular-Pair Abnormalities

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous inherited disorder arising from dysmotility of motile cilia and sperm. This is associated with a variety of ultrastructural defects of the cilia and sperm axoneme that affect movement, leading to clinical consequences on respiratory-tract mucociliary clearance and lung function, fertility, and left-right body-axis determination. We performed whole-genome SNP-based linkage analysis in seven consanguineous families with PCD and central-microtubular-pair abnormalities. This identified two loci, in two families with intermittent absence of the central-pair structure (chromosome 6p21.1, Zmax 6.7) and in five families with complete absence of the central pair (chromosome 6q22.1, Zmax 7.0). Mutations were subsequently identified in two positional candidate genes, RSPH9 on chromosome 6p21.1 and RSPH4A on chromosome 6q22.1. Haplotype analysis identified a common ancestral founder effect RSPH4A mutation present in UK-Pakistani pedigrees. Both RSPH9 and RSPH4A encode protein components of the axonemal radial spoke head. In situ hybridization of murine Rsph9 shows gene expression restricted to regions containing motile cilia. Investigation of the effect of knockdown or mutations of RSPH9 orthologs in zebrafish and Chlamydomonas indicate that radial spoke head proteins are important in maintaining normal movement in motile, “9+2”-structure cilia and flagella. This effect is rescued by reintroduction of gene expression for restoration of a normal beat pattern in zebrafish. Disturbance in function of these genes was not associated with defects in left-right axis determination in humans or zebrafish

Composição florística e análise fitogeográfica de uma floresta semidecídua na Bahia, Brasil

The semideciduous forests of Bahia occur as highly fragmented areas and have only received a little attention from floristic and phytogeographical studies. These areas are mainly situated within the semi-arid region and isolated from the Coastal Atlantic Forest by the surrounding dry vegetation of the caatinga domain. This paper presents a floristic survey of a semideciduous forest fragment at Serra da Fazenda Retiro (SFR), Feira de Santana, Bahia State, in order to assess its phytogeographical relationships in comparison to caatinga vegetation and Atlantic Forest. The survey identified 173 species belonging to 143 genera and 59 families. Myrtaceae presented the highest species number (15 spp.), followed by Euphorbiaceae (13), Leguminosae (12), Malvaceae (7), Orchidaceae (7), and Rubiaceae (7). Additionally, three new species of the genera Neomarica (Iridaceae), Pseudobombax (Malvaceae), and Solanum (Solanaceae) were sampled. In spite of the studied area being located within the circumscription of the Caatinga Biome, analysis of similarity (UPGMA) and of the SFR species composition showed that it is more floristically related to semideciduous forest of the Atlantic Forest domain rather than to caatinga vegetation. © 2009 Instituto de Pesquisas Jardim Botanico do Rio de Janeiro. All Rights Reserved