In most mammals, sexual fate is determining genetically by the presence of the SRY gene which encoded the testis-determining factors on the Y chromosome. Likewise, avian sex is determined genetically. At day 3.5 (stage 22; HH) in chicken embryogenesis, the gonadal primordium begins forming. Thus, to identify the novel sex-determinating genes in early chicken embryos, subtractive cDNA libraries from male-minus-female (M-F) and female-minus-male (F-M) of 3 Dpc. embryos were established. Both collected male and female chicken total mRNAs were purified using Dynabeads. After a blund-end restriction endonuclease Rsa I digestion of cDNA, adaptor ligation for tester cDNA was performed. When first and second cDNA hybridization was finished, those nonredundant cDNA between tester and driver will be amplified by two rounds of PCR. Subsequently, TA-cloning was performed and the cDNA fragments were PCR-amplified using M13 primers. PCR products of Clones were first screened by differential screening hybridization to decrease false positive inserts. Then, gene annotation was carried out by data-mining in public databases, GeneBank (NCBI, USA). Finally, 40 known and 71 novel transcripts of M-F cDNA library, 88 known and 128 novel transcripts of F-M cDNA library were identified. In M-F subtracted library, 4 identified known genes were located on Z sex chromosome such as WD repeat domain 36 (WDR36), PC4 and SFRS1 interacting protein 1 (PSIP1), serum response factor binding protein 1 (SRFBP1) and glycine dehydrogenase (decarboxylating) (GLDC). Another two identified known genes, laminin alpha 1 (LAMA1) and leukocyte cell derived chemotaxin 1 (LECT1) were reported be relate to cell differentiation and development. In F-M subtracted library, only Wpkic-8 was located on W sex chromosome. Other identified genes like slowmo homolog 2 (Drosophila) (SLMO2), collagen, type IV, alpha 1 (COL4A1), anterior gradient 2 homolog (Xenopus laevis), transcript variant 2 (AGR2), solute carrier family 25 (mitochondrial carrier; adenine nucleotide translocator), member 6 (SLC25A6) and prolyl endopeptidase (PREP) were also found expressed higer in human ovary then testis. PREP was proposed that it may play a role in mediating sperm death by regulating the levels of thyrotropin-releasing hormone analogs and in mediating sperm death associated with necrozoospermia. These transcripts located on W or Z sex chromosome identified from subtracted libraries may play an important role in sex determination mechanism.

Made available in DSpace on 2014-12-17T14:03:38Z (GMT). No. of bitstreams: 1 RenataKSE_DISSERT.pdf: 1992793 bytes, checksum: 77e111c6a7208973429d97e0cf1a51eb (MD5) Previous issue date: 2011-09-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Flowering is a fundamental process in the life cycle for plant. This process is marked by vegetative to reproductive apical meristem conversion, due to interactions between several factors, both internal and external to plant. Therefore, eight subtractive libraries were constructed using apical meristem induced or not induced for two contrasting species: Solanum lycopersicum cv. Micro-Tom and Solanum pimpinellifolium. Several cDNAs were identified and among these, were selected two cDNAs: one homologous cDNA to cyclophilin (LeCYP1) and the other to Auxin repressed protein (ARP). It has observed that LeCYP1 and ARP genes are important in the developmental process to plants. In silico analysis, were used several databases with the exclusion criterion E-value <1.0x10-15. As a result, conservation was observed for proteins analyzed by means of multiple alignments and the presence of functional domains. Then, overexpression cassettes were constructed for the ARP cDNA in sense and antisense orientations. For this step, it was used the CaMV35S promoter. The cDNA orientation (sense or antisense) in relation to the promoter was determined by restriction enzymes and sequencing. Then, this cassette was transferred to binary vector pZP211 and these cassettes were transferred into Agrobacterium tumefaciens LBA4404. S. lycopersicum cv. Micro-Tom (MT) and MT-Rg1 plants were transformed. In addition, seedlings were subjected to hormone treatments using a synthetic auxin (&#61537;- naphthalene acetic acid) and cyclosporin A (cyclophilin inhibitor) treatments and it was found that the hormone treatment there were changes in development of lateral roots pattern, probably related to decreases in auxin signaling caused by reduction of LeCYP1 in MT-dgt plants while cyclosporin A treatments, there was a slight delay in flowering in cv. MT plants. Furthermore, assay with real-time PCR (RT-qPCR) were done for expression level analysis from LeCYP1 and ARP in order to functionally characterize these sequences in tomato plants. / A flora??o ? fundamental no ciclo de vida de uma planta. Este processo ? marcado pela convers?o do meristema apical vegetativo em reprodutivo, devido a intera??es entre diversos fatores, tanto internos quanto externos ? planta. Diante disso, foram constru?das oito bibliotecas subtrativa utilizando ?pices meristem?ticos induzidos e n?o induzidos para a flora??o de duas esp?cies de tomateiro: Solanum lycopersicum cv Micro-Tom e S. pimpinellifolium. In?meros cDNAs foram identificados e dentre estes, foram selecionados o cDNA hom?logo a ciclofilina (LeCYP1) e a Prote?na Reprimida por Auxina (ARP) para a caracteriza??o in silico e funcional em esp?cie de tomateiro. Tem sido observado em outros sistemas vegetais que os genes LeCYP1 e ARP s?o importantes no processo de desenvolvimento da planta. Na an?lise in silico, foram utilizados diversos bancos de dados, tendo como crit?rio de exclus?o o E-value <1.0x10-15. Uma conserva??o para as prote?nas analisadas foi observada por meio dos alinhamentos m?ltiplos e a presen?a de dom?nios funcionais. Em seguida, foram realizadas constru??es de cassetes de superexpress?o para o cDNA hom?logo ? ARP em orienta??o senso e antissenso. Para esta etapa, foi utilizado o promotor forte CaMV35S presente no vetor intermedi?rio pBC (Stratagene). A orienta??o do cDNA (senso ou antissenso) em rela??o ao promotor foi determinada por meio de enzimas de restri??o e sequenciamento dos potenciais clones. Em seguida, este cassete foi transferido para o vetor bin?rio pZP211 e os clones obtidos foram confirmados pelo padr?o de restri??o utilizando diferentes enzimas. Subsequentemente, estes cassetes foram transferidos para a Agrobacterium tumefaciens LBA4404 e posteriormente transformado em plantas de S. lycopersicum cv. Micro-Tom (MT) e MT-Rg1. Em adi??o, pl?ntulas foram submetidas a tratamentos hormonais utilizando uma auxina sint?tica (?cido &#61537;-naftaleno ac?tico) e com ciclosporina A (inibidor de ciclofilina) e foi constatado que no tratamento hormonal houve altera??es no padr?o de desenvolvimento das ra?zes laterais, provavelmente relacionada ao d?ficit na sinaliza??o da auxina ocasionada pela redu??o de LeCYP1 em plantas MT-dgt, enquanto que no tratamento com ciclosporina A, ocorreu um atraso no florescimento de plantas cv MT. Al?m disso, ensaios de PCR em tempo real (RT-qPCR) foram efetuados para an?lise de express?o dos cDNAs hom?logos a LeCYP1 e ARP de modo a caracterizarmos funcionalmente estas sequ?ncias em plantas de tomateiro.