A conserved RWP-RK transcription factor VSR1 controls gametic differentiation in volvocine algae.

Volvocine green algae are a model for understanding the evolution of mating types and sexes. They are facultatively sexual, with gametic differentiation occurring in response to nitrogen starvation (-N) in most genera and to sex inducer hormone in . The conserved RWP-RK family transcription factor (TF) MID is encoded by the mating-type locus or male sex-determining region of heterothallic volvocine species and dominantly determines or male gametic differentiation.

BRASSINOSTEROID-SIGNALING KINASE 3, a plasma membrane-associated scaffold protein involved in early brassinosteroid signaling.

Brassinosteroids (BRs) are steroid hormones essential for plant growth and development. The BR signaling pathway has been studied in some detail, however, the functions of the BRASSINOSTEROID-SIGNALING KINASE (BSK) family proteins in the pathway have remained elusive. Through forward genetics, we identified five semi-dominant mutations in the BSK3 gene causing BSK3 loss-of-function and decreased BR responses.

Evolutionary divergence of the sex-determining gene uncoupled from the transition to anisogamy in volvocine algae.

Volvocine algae constitute a unique comparative model for investigating the evolution of oogamy from isogamous mating types. The sex- or mating type-determining gene encodes a conserved RWP-RK transcription factor found in either the or male mating locus of dioecious volvocine species. We previously found that from the isogamous species () could not induce ectopic spermatogenesis when expressed heterologously in females, suggesting coevolution of Mid function with gamete dimorphism.

Identification of Chlamydomonas reinhardtii endogenous genic flanking sequences for improved transgene expression.

Chlamydomonas reinhardtii is a unicellular green alga that has attracted interest due to its potential biotechnological applications, and as a model for algal biofuel and energy metabolism. Despite all the advantages that this unicellular alga offers, poor and inconsistent expression of nuclear transgenes remains an obstacle for basic and applied research. We used a data-mining strategy to identify highly expressed genes in Chlamydomonas whose flanking sequences were tested for the ability to drive heterologous nuclear transgene expression.

Evolution of sexes from an ancestral mating-type specification pathway.

Male and female sexes have evolved repeatedly in eukaryotes but the origins of dimorphic sexes and their relationship to mating types in unicellular species are not understood. Volvocine algae include isogamous species such as Chlamydomonas reinhardtii, with two equal-sized mating types, and oogamous multicellular species such as Volvox carteri with sperm-producing males and egg-producing females. Theoretical work predicts genetic linkage of a gamete cell-size regulatory gene(s) to an ancestral mating-type locus as a possible step in the evolution of dimorphic gametes, but this idea has not been tested.

Species and population level molecular profiling reveals cryptic recombination and emergent asymmetry in the dimorphic mating locus of C. reinhardtii.

Heteromorphic sex-determining regions or mating-type loci can contain large regions of non-recombining sequence where selection operates under different constraints than in freely recombining autosomal regions. Detailed studies of these non-recombining regions can provide insights into how genes are gained and lost, and how genetic isolation is maintained between mating haplotypes or sex chromosomes. The Chlamydomonas reinhardtii mating-type locus (MT) is a complex polygenic region characterized by sequence rearrangements and suppressed recombination between its two haplotypes, MT+ and MT-.

Evolution of an expanded sex-determining locus in Volvox.

Although dimorphic sexes have evolved repeatedly in multicellular eukaryotes, their origins are unknown. The mating locus (MT) of the sexually dimorphic multicellular green alga Volvox carteri specifies the production of eggs and sperm and has undergone a remarkable expansion and divergence relative to MT from Chlamydomonas reinhardtii, which is a closely related unicellular species that has equal-sized gametes. Transcriptome analysis revealed a rewired gametic expression program for Volvox MT genes relative to Chlamydomonas and identified multiple gender-specific and sex-regulated transcripts.

Rearranged T-cell receptor gene and positive Epstein-Barr virus-encoded nuclear RNA in an extranodal NK/T-cell lymphoma with cutaneous manifestation only: case study.

Natural killer (NK)/cytotoxic T-cell lymphoma, a new type of cutaneous neoplasm, has been described recently in the World Health Organization/European Organization for Research and Treatment of Cancer classification for cutaneous lymphomas. We report an 11-year-old boy who had had erythematous plaques and blisters on his face and hands for 4 years and infiltrating plaques and necrosis on his extremities for 4 months. Routine clinical and laboratory examinations found no primary nasal involvement.

Anther-specific expression of ipt gene in transgenic tobacco and its effect on plant development.

Isopentenyl transferase (ipt) gene from Agrobacterium tumefaciens T-DNA was placed under the control of a TA29 promoter which expresses specifically in anther. The chimeric TA29-ipt gene was transferred to tobacco plants. During flowering, mRNA of the ipt gene in the anthers of the transgenic plants accumulated and the level of iPA + iPs increased 3-4-fold in the leaves, petals, pistils, and stamens compared with those in the wild type plants.